@article{rabiei_cance_chacko_2024, title={A Study on Welding of Porous Metals and Metallic Foams}, url={https://doi.org/10.1002/adem.202470008}, DOI={10.1002/adem.202470008}, abstractNote={Advanced Engineering MaterialsVolume 26, Issue 4 2470008 Inside Front CoverFree Access A Study on Welding of Porous Metals and Metallic Foams Afsaneh Rabiei, Corresponding Author Afsaneh Rabiei [email protected] orcid.org/0000-0002-1091-424X Department of Mechanical and Aerospace Engineering, North Carolina State University, 1840 Entrepreneur Dr., Raleigh, NC, 27695-7910 USASearch for more papers by this authorJohn Cance, John Cance Department of Mechanical and Aerospace Engineering, North Carolina State University, 1840 Entrepreneur Dr., Raleigh, NC, 27695-7910 USASearch for more papers by this authorZubin Chacko, Zubin Chacko Department of Mechanical and Aerospace Engineering, North Carolina State University, 1840 Entrepreneur Dr., Raleigh, NC, 27695-7910 USASearch for more papers by this author Afsaneh Rabiei, Corresponding Author Afsaneh Rabiei [email protected] orcid.org/0000-0002-1091-424X Department of Mechanical and Aerospace Engineering, North Carolina State University, 1840 Entrepreneur Dr., Raleigh, NC, 27695-7910 USASearch for more papers by this authorJohn Cance, John Cance Department of Mechanical and Aerospace Engineering, North Carolina State University, 1840 Entrepreneur Dr., Raleigh, NC, 27695-7910 USASearch for more papers by this authorZubin Chacko, Zubin Chacko Department of Mechanical and Aerospace Engineering, North Carolina State University, 1840 Entrepreneur Dr., Raleigh, NC, 27695-7910 USASearch for more papers by this author First published: 26 February 2024 https://doi.org/10.1002/adem.202470008AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Graphical Abstract Metallic Foams In article number 2301430, Afsaneh Rabiei, John Cance, and Zubin Chacko present a composite metal foam (CMF) as the first porous metal successfully welded using an induction method. The process is possible due to the presence of the metallic matrix between CMF porosities, allowing the penetration of eddy currents, plus the low thermal conductivity of CMF, concentrating the heat at the joint leaving the rest of the CMF cool to the touch. Volume26, Issue4Special Issue:25 Years of Advanced Engineering MaterialsFebruary 20242470008 RelatedInformation}, journal={Advanced Engineering Materials}, author={Rabiei, Afsaneh and Cance, John and Chacko, Zubin}, year={2024}, month={Feb} }
 @article{amoafo-yeboah_rabiei_2024, title={Thermal Emissivity and Heat Capacity of Composite Metal Foam}, url={https://doi.org/10.3390/jcs8060202}, DOI={10.3390/jcs8060202}, abstractNote={Composite metal foam (CMF) is a new class of material based on a mixture of metal matrix composites and metal foams. While the mechanical properties of CMF are well studied, its thermal properties, particularly at extreme temperatures, are yet to be evaluated and established. This study investigates the specific heat capacity of stainless-steel composite metal foam at temperatures up to 1200 °C while comparing data obtained using the laser flash method and a differential scanning calorimetry method (DSC). Moreover, it outlines a detailed procedure for investigating the surface emissivity of composite metal foam (CMF) as a function of the emissivity of separate components (spheres and matrix). It uses experimental and analytical procedures to show how emissivity is directly affected by surface roughness, temperature, sphere curvature and viewing angles. The CMF used in this study consists of 316L stainless steel matrix and stainless-steel hollow spheres with varying sphere sizes.}, journal={Journal of Composites Science}, author={Amoafo-Yeboah, Nigel and Rabiei, Afsaneh}, year={2024}, month={May} }
 @article{rabiei_cance_chacko_2023, title={A Study on Welding of Porous Metals and Metallic Foams}, volume={11}, ISSN={["1527-2648"]}, url={https://doi.org/10.1002/adem.202301430}, DOI={10.1002/adem.202301430}, abstractNote={Metal foams are lightweight materials with exceptional impact energy absorption and unique thermal properties. Integrating these novel materials into large structural components requires developing appropriate welding techniques that preserve their bulk performance. Traditional fusion welding methods are ill‐suited for metal foams due to their porous structure, which tends to be filled during welding, compromising performance. This study focuses on solid‐state welding techniques, including friction stir welding (FSW) and induction welding, to join metal foams without adversely affecting their cellular structure. The results reveal challenges with FSW; it generates excessive heat during welding, filling the foam's porosities and disrupting its cellular structure. In contrast, induction welding is an effective method for joining composite metal foam (CMF) panels without compromising their structural integrity. The matrix between the porosities in CMF facilitates the penetration of eddy current, promoting the induction welding process. The mechanical properties of the weldments are studied through uniaxial tensile tests, while microstructural characterization of the weldment is evaluated using scanning electron microscopy. The results provide insight into the effect of various welding parameters (e.g., welding temperature, workpiece thickness, and welding environment) as well as the suitability and restrictions of such welding methods in joining CMFs.}, journal={ADVANCED ENGINEERING MATERIALS}, author={Rabiei, Afsaneh and Cance, John and Chacko, Zubin}, year={2023}, month={Nov} }
 @article{chacko_amoafo-yeboah_cance_rabiei_2023, title={A computational and experimental approach to evaluate thermal conductivity and diffusivity of steel composite metal foam}, volume={9}, ISSN={["1588-2926"]}, url={https://doi.org/10.1007/s10973-023-12515-4}, DOI={10.1007/s10973-023-12515-4}, journal={JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY}, author={Chacko, Zubin and Amoafo-Yeboah, Nigel and Cance, John and Rabiei, Afsaneh}, year={2023}, month={Sep} }
 @article{yan_yu_ding_li_rabiei_bowen_2023, title={Dwell-fatigue crack growth behaviour of Alloy 709}, volume={249}, ISSN={["1873-2453"]}, DOI={10.1016/j.actamat.2023.118808}, abstractNote={Dwell-fatigue crack growth behaviour of an advanced austenitic stainless steel Alloy 709 has been investigated and compared with that of a conventional Type 316H stainless steel. The test procedure employed alternation of 1 h dwell-fatigue loading and 0.25 Hz fast cycling so that crack growth rates (da/dN) obtained from dwell-fatigue loading can be compared to those purely result from fatigue mechanism on the same test-piece. Tests were conducted at 550, 650 and 750 °C in air using 0.5 T compact tension test-pieces under a fixed maximum load of 8 kN and a stress ratio, R, of 0.1. For the investigated temperature and ΔK ranges, crack growth mechanisms of fatigue alone, creep alone and mixed fatigue-creep have all been observed. Detailed fractographic and metallographic observations were conducted to interpret failure mechanisms and regimes of different failure modes. Compared to crack growth rates obtained under 0.25 Hz fatigue loading, dwell-fatigue produces: no obvious increases in crack growth rates at a test temperature of 550 °C; a moderate increase (∼ 2–5 times) at a test temperature of 650 °C; and, over a tenfold increase at a test temperature of 750 °C. Compared to 316H, Alloy 709 has much improved resistance against creep-fatigue crack growth, here confirmed at the single test temperature of 650 °C.}, journal={ACTA MATERIALIA}, author={Yan, Jin and Yu, Suyang and Ding, Rengen and Li, Hangyue and Rabiei, Afsaneh and Bowen, Paul}, year={2023}, month={May} }
 @article{amoafo-yeboah_rabiei_2023, title={Thermal Response of Steel-Steel Composite Metal Foams under Small-Scale Torch-Fire Conditions}, volume={6}, ISSN={["1527-2648"]}, url={https://doi.org/10.1002/adem.202300217}, DOI={10.1002/adem.202300217}, abstractNote={Steel–steel composite metal foam (S–S CMF) is a novel metal matrix composite material characterized by its high strength‐to‐weight ratio and unique mechanical and thermal properties. It is made up of hollow stainless‐steel spheres, embedded in stainless steel matrix, with 65–70% air in the structure making it effective as an insulating material. S–S CMF is being explored for use in tank cars carrying hazardous materials (HAZMATs) as a potential partial replacement for conventional carbon steel and thermal insulating material currently being used. In this study, S–S CMF material is numerically and experimentally evaluated for its thermal protection performance. Experimental studies are conducted in scaled‐down jet fire condition while numerical studies are conducted using fire dynamics simulator (FDS). Based on experimental and modeling results, as well as uncertainty studies, 13–15 mm thick S–S CMF ranging in density of about 2.5 g cc−1 tested as novel structural/insulating material meets the acceptance criterion for small‐scale simulated torch‐fire testing. Further success is anticipated in future full‐scale evaluation of 122 × 122 cm samples. The outstanding fire resistance and thermal protection of S–S CMF is attributed to the substantial volume of air trapped within the material, which correlates to its total density.}, journal={ADVANCED ENGINEERING MATERIALS}, author={Amoafo-Yeboah, Nigel and Rabiei, Afsaneh}, year={2023}, month={Jun} }
 @article{amoafo-yeboah_rabiei_2023, title={Thermal Response of Steel-Steel Composite Metal Foams under Small-Scale Torch-Fire Conditions}, volume={25}, ISSN={["1527-2648"]}, url={https://doi.org/10.1002/adem.202370064}, DOI={10.1002/adem.202370064}, abstractNote={The performance of novel steel composite metal foam (CMF) in a torch fire environment of 1200C is compared with that of the currently used solid steel of the same thickness as described in article number 2300217 by Afsaneh Rabiei and Nigel Amoafo-Yeboah. While solid steel is three times heavier, its temperature exceeds 730C in 30 minutes exposure but the steel CMF barely reaches 400C, providing a safer way for transportation of HAZMAT.}, number={19}, journal={ADVANCED ENGINEERING MATERIALS}, author={Amoafo-Yeboah, Nigel and Rabiei, Afsaneh}, year={2023}, month={Oct} }
 @article{rabiei_amoafo-yeboah_huseboe_scemama_2022, title={A Study on Thermal Properties of Composite Metal Foams for Applications in Tank Cars Carrying Hazardous Materials}, ISBN={["978-3-030-92566-6"]}, ISSN={["2367-1696"]}, DOI={10.1007/978-3-030-92567-3_23}, abstractNote={Each year, millions of tons of hazardous materials are shipped through tank cars on railroads. Accidents involving these tank cars can create punctures that release these hazardous materials into the surrounding area, resulting in potential fire and even explosions, human fatalities, and substantial damage to the environment. Despite all enhancements to mitigate the consequences of such accidents, there is still an immediate need for novel material with superior puncture and fire resistance with lower weight than the current carbon-steel in use, to improve the safety and efficacy of tank cars carrying hazardous materials (HAZMAT). Composite metal foamComposite metal foam (CMF) is a novel class of light-weight material made of closely packed metallic hollow spheres with a surrounding metallic matrix. In this study, the latest developments on evaluating the performance of composite metal foamComposite metal foam against extreme heat through both experimental and analytical approaches will be reported and compared to those properties of the base bulk steel materials in use.}, journal={METAL-MATRIX COMPOSITES: ADVANCES IN PROCESSING, CHARACTERIZATION, PERFORMANCE AND ANALYSIS}, author={Rabiei, Afsaneh and Amoafo-Yeboah, Nigel and Huseboe, Evan and Scemama, Claire}, year={2022}, pages={367–379} }
 @article{lall_bowen_rabiei_2022, title={A numerical and experimental approach to compare the effect of sample thickness in small in-situ SEM and large ex-situ tensile testing in Alloy 709}, volume={184}, ISSN={["1873-4189"]}, DOI={10.1016/j.matchar.2021.111614}, abstractNote={ASTM standards for tensile tests define specific sample size requirements regardless of grain size of the material. However, sample size requirements for testing should be considered in conjunction with the number of grains within its reduced cross-sectional area. This is particularly important for in-situ Scanning Electron Microscope (SEM) tensile tests, as they have to be conducted on smaller samples. In this study, a comprehensive experimental and numerical evaluation of the effect of specimen thickness (and the resulting number of grains within the cross-section) were conducted using in-situ SEM tensile test (on sub-millimeter thick samples) and ex-situ tensile tests (on samples of 0.68–5.9 mm thickness) and the results are compared with FEM simulations outcome. All tests were conducted at room temperature and the results are correlated to the number of grains within the thickness of specimens. The tensile test results indicated that even though the 0.2% proof stress and the tensile strength do not vary for the current range of thicknesses (with number of grains in the cross-section varying from 13 to 118), a difference in necking mechanism exists. Post tensile strength, thinner samples undergo more shear failure and diagonal localized necking whereas thicker samples experience more diffuse necking indicated by decreased area of shear failure at the edges and increased area of dimpled tensile failure at the center of the sample. FEM results complement the experimental findings by showing the formation of conjugated localized shear bands on the upper and lower surface in the 0.68 mm thick sample and shear bands combining to form singular shear bands in thicker samples. These results also confirm the validity of the in-situ SEM tensile tests conducted on thinner samples as long as the required minimum number of grains exist within the cross-section.}, journal={MATERIALS CHARACTERIZATION}, author={Lall, Amrita and Bowen, Paul and Rabiei, Afsaneh}, year={2022}, month={Feb} }
 @article{lall_bowen_rabiei_2022, title={A study on the creep behavior of alloy 709 using in-situ scanning electron microscopy}, volume={183}, ISSN={["1873-4189"]}, DOI={10.1016/j.matchar.2021.111587}, abstractNote={In this research, an experimental evaluation of creep properties of Alloy 709 in the temperature range of 750–850 °C was undertaken. Alloy 709 is a novel austenitic stainless steel with 20% Cr and 25% Ni by wt% that was developed for application in structural components of nuclear power plants. Creep rupture tests were conducted in an in-situ heating-loading and Scanning Electron Microscope (SEM) unit equipped with Electron Backscatter Diffraction (EBSD) detector and Energy Dispersive Spectroscopy (EDS). "Real-time" creep damage mechanisms of Alloy 709 at various stresses and temperatures using a flat, un-notched sample with continuously reducing cross-section is studied so that the failure and maximum creep damage occurred at the center of the sample where the in-situ SEM imaging could be focused. Accelerated creep tests at temperatures and stresses above service conditions were performed by employing multiple blocks of constant loads where the loads were increased once the sample attained constant creep rate, indicating a secondary creep regime. This technique ensures multiple data points can be obtained from the same test, saves the time required for an otherwise long-term creep test and usage of SEM. Coincident Site Lattice (CSL) boundary maps were collected as control maps before testing, and the grain boundaries were observed during the creep test to understand the effect of grain boundary character on the creep damage mechanism. Void growth, grain boundary separation, and sliding were found to be the main creep mechanisms whose rate is dependent on stress and temperature. Failure mechanisms studied on the fracture surface using SEM fractography were correlated to the sample surface observations to create complementary information to better understand the underline creep mechanism of Alloy 709.}, journal={MATERIALS CHARACTERIZATION}, author={Lall, Amrita and Bowen, Paul and Rabiei, Afsaneh}, year={2022}, month={Jan} }
 @article{lall_bowen_rabiei_2021, title={Effect of aging on failure mechanism of Alloy 709 at various temperatures}, volume={171}, ISSN={["1873-4189"]}, DOI={10.1016/j.matchar.2020.110750}, abstractNote={Alloy 709 is a novel austenitic stainless steel with high temperature creep strength, weldability, and corrosion resistance. These properties make the material suitable for applications in the structure of next-generation nuclear power plants. Enduring high temperatures for an extended period of time in the harsh environments of a nuclear power plant results in thermal aging of the material. Therefore, it is imperative to study the effect of thermal aging on the microstructure and mechanical properties of Alloy 709 before its application in the next generation power plants. In this study, hot-processed (forged + rolled), annealed and quenched ingots of Alloy 709 are aged at 650 °C for 2000 h in air and then tested at various temperatures up to 850 °C in an in-situ heating-loading Scanning Electron Microscope (SEM) equipped with Energy Dispersive Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD). The effect of testing temperature and aging on microstructural evolutions during tensile testing of as-received and aged samples are studied. Both as-received and aged samples displayed serrations and drop in ductility at elevated temperatures, due to the effect of dynamic strain aging (DSA). The occurrence of DSA activity was found within temperatures range of 500 °C–750 °C in as-received and 550 °C - 650 °C in aged samples. The aged samples showed less elongation accompanied by shallower dimples on the fractured surface, indicating less ductile failure mechanism compared to as-received samples. Failure mechanism observations on the fracture surface using SEM fractography are correlated to the observations made on the sample surface using in-situ SEM to achieve a complementary set of information to better understand the failure mechanism of this novel alloy.}, journal={MATERIALS CHARACTERIZATION}, author={Lall, Amrita and Bowen, Paul and Rabiei, Afsaneh}, year={2021}, month={Jan} }
 @article{lall_ding_bowen_rabiei_2021, title={In-situ Scanning Electron Microscopic Observation of Creep and Creep-Fatigue of Alloy 709}, ISBN={["978-3-030-65260-9"]}, ISSN={["2367-1696"]}, DOI={10.1007/978-3-030-65261-6_75}, abstractNote={Alloy 709 is a 20Cr-25Ni advanced austenitic stainless steel developed as an improvement over the existing advanced austenitic stainless steels. The alloy’s high Ni content provides increased austenite stability, while its high Cr content improves its corrosion resistance at extreme environments of nuclear structures. In this study, in-situ scanning electron microscope (SEM) tensile, creep and creep-fatigue tests at various temperatures from room temperature to 1000 °C will be reported. Electron backscatter diffraction (EBSD) and energy dispersive X-ray spectrometry (EDS) were used to observe the microstructural evolution and phase change during the in-situ heating and loading at different temperatures and strain rates and identify the dominant deformation mechanisms in each environmental condition.}, journal={TMS 2021 150TH ANNUAL MEETING & EXHIBITION SUPPLEMENTAL PROCEEDINGS}, author={Lall, Amrita and Ding, Rengen and Bowen, Paul and Rabiei, Afsaneh}, year={2021}, pages={839–852} }
 @article{rabiei_lattimer_bearinger_2021, title={Recent Advances in the Analysis, Measurement, and Properties of Composite Metal Foams}, ISBN={["978-3-030-65248-7"]}, ISSN={["2367-1696"]}, DOI={10.1007/978-3-030-65249-4_13}, abstractNote={Composite metal foam (CMF) is a novel lightweight metal matrix composite material with lightweight, high strength to density ratio and high energy absorption capabilities. The material can be made out of many different metals, alloys, and combinations, e.g. aluminum, steel, titanium, etc. For example, it can be made 100% out of steel, but, due to its porosities, it will weigh as light as aluminum. CMF is made of closely packed metallic hollow spheres with a metallic matrix that fills the empty spaces in between spheres. In every combination of the spheres and matrix materials, the final product weight will be ~30–35% of the weight of the parent material; the rest would be the air trapped inside its porosities. In this study, a scaled-down version of the torch fire experiments specified in 49 Code of Federal Regulation (CFR) Part 179, Appendix B was developed to provide initial data on evaluating the thermal protection performance of steel-steel composite metal foam (S-S CMF) in the torch fire conditions. S-S CMF panels of 30 × 30 cm dimensions are manufactured and tested to evaluate their survivability when exposed to a 30-minute torch fire condition of high velocity jet fire with a gas temperature of 1204°C in accordance with 49 CFR Part 179. Testing was performed to characterize the jet burner gas temperature and velocity flow field, and a calibration fire test was conducted using steel only as required by the test specification. The assembly was tested in duplicate in two consecutive simulated torch fire exposures as specified in 49 CFR Part 179, Appendix B. Based on the experimental results, a 15 mm thick steel-steel composite metal foam tested as novel insulation system met the acceptance criteria for the simulated torch fire testing and is expected to pass when tested at a full size of 122 × 122 cm dimensions. The main factor for fire resistance and thermal protection performance of S-S CMF is attributed to the large air content in the material.}, journal={METAL-MATRIX COMPOSITES: ADVANCES IN ANALYSIS, MEASUREMENT, AND OBSERVATIONS}, author={Rabiei, Afsaneh and Lattimer, Brian Y. and Bearinger, Elias}, year={2021}, pages={201–216} }
 @article{rabiei_karimpour_janssens_basu_2021, title={Simulated pool fire testing and modeling of a composite metal foam}, volume={45}, ISSN={["1099-1018"]}, url={https://doi.org/10.1002/fam.2912}, DOI={10.1002/fam.2912}, abstractNote={Summary}, number={3}, journal={FIRE AND MATERIALS}, author={Rabiei, Afsaneh and Karimpour, Kamellia and Janssens, Marc and Basu, Debashis}, year={2021}, month={Apr}, pages={379–386} }
 @article{marx_rabiei_2021, title={Tensile properties of composite metal foam and composite metal foam core sandwich panels}, volume={23}, ISSN={["1530-7972"]}, url={https://doi.org/10.1177/1099636220942880}, DOI={10.1177/1099636220942880}, abstractNote={ Steel-steel composite metal foam (SS-CMF) and composite metal foam core sandwich panels (SS-CMF-CSP) were manufactured and tested under quasi-static tension. The SS-CMF-CSP were manufactured by attaching stainless steel face sheets to a SS-CMF core using solid-state diffusion bonding. SEM imaging was used to inspect the microstructure of SS-CMF and compare it to that of SS-CMF-CSP. The results indicate a cohesive bond line at the interface of the core and the face sheets. The bare SS-CMF samples had an ultimate tensile strength between 75–85 MPa and a failure strain between 7.5–8%. The normalized tensile strength of the SS-CMF was approximately 24 MPa/(g/cm3), 410% higher than other comparable metal foams, with a specific energy absorption of 0.95 J/g under tension. The uniform porosities and strong bonding between the sphere wall and matrix seem to be the strengthening factor of SS-CMF under tension when compared to other metal foams. The ultimate tensile strength of the SS-CMF-CSP was 115% stronger than the bare SS-CMF at 165 MPa with an average failure strain of 23%. The normalized strength of the SS-CMF-CSP was 52% higher than the bare SS-CMF. The modulus of elasticity was approximated using the rule of mixtures for the SS-CMF and the SS-CMF-CSP and the experimental results were found to lie within the calculated upper and lower bounds. }, number={8}, journal={JOURNAL OF SANDWICH STRUCTURES & MATERIALS}, publisher={SAGE Publications}, author={Marx, Jacob and Rabiei, Afsaneh}, year={2021}, month={Nov}, pages={3773–3793} }
 @article{rabiei_portanova_marx_scott_schwandt_2020, title={A Study on Puncture Resistance of Composite Metal Foam Core Sandwich Panels}, volume={22}, ISSN={["1527-2648"]}, url={https://doi.org/10.1002/adem.202000693}, DOI={10.1002/adem.202000693}, abstractNote={Steel–steel composite metal foam‐core sandwich panels (S‐S CMF‐CSP) with variety of thicknesses of components (face sheets and cores) are manufactured by attaching stainless steel face sheets to a S‐S CMF core using either solid‐state diffusion bonding or adhesion bonding. Scanning electron microscope imaging is used to evaluate the microstructure of diffusion bonded panels particularly at the interface of the core and face sheets. The puncture resistance of the sandwich panels is evaluated using a 0.50 caliber Mann gun barrel, modified to fire 2.54 and 3.175 cm diameter steel balls creating kinetic puncture energies up to 14 500 J. But, no complete penetrations through any of the sandwich panels are achieved. At lower impact velocities, tensile stresses resulted from the sudden changes in mechanical impedance between various layers of the sandwich panel recoil the ball back while at higher impact velocities, the high strain rate deformation at the point of impact along with the friction heat between the ball and panel surface fuses the ball to the target instantly resulting in debonding of adhesively bonded panels, whereas the diffusion bonded panels resist better. Sandwich panels with higher areal densities and thicker face sheets did not show major advantages over the panels with thinner face sheets.}, number={12}, journal={ADVANCED ENGINEERING MATERIALS}, author={Rabiei, Afsaneh and Portanova, Marc and Marx, Jacob and Scott, Christopher and Schwandt, Jerod}, year={2020}, month={Dec} }
 @article{yu_yan_li_ding_lall_rabiei_bowen_2020, title={Fatigue crack growth resistance of the austenitic stainless steel Alloy 709 at elevated temperatures}, volume={9}, ISSN={["2214-0697"]}, url={https://doi.org/10.1016/j.jmrt.2020.09.050}, DOI={10.1016/j.jmrt.2020.09.050}, abstractNote={Fatigue crack growth resistance of an austenitic stainless steel Alloy 709 has been evaluated at temperatures of 550, 650 and 750 °C in air and vacuum. Tests were conducted at a frequency of 0.25 Hz and a stress ratio of 0.1. The linear elastic stress intensity factor range (ΔK) has been used to characterise fatigue crack growth resistance. A modest detrimental effect of air at elevated temperatures on fatigue crack growth is identified and discussed. Striated transgranular fatigue is found to be the failure mechanism for all test conditions. The formation of striations and the interaction of crack growth with slip traces are further investigated using in-situ testing (within a scanning electron microscope), together with transmission electron microscopy carried out on samples extracted by focused ion-beam milling perpendicular to fracture surfaces. Finally, an analytical model is proposed to predict fatigue crack growth in air for Alloy 709.}, number={6}, journal={JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T}, publisher={Elsevier BV}, author={Yu, Suyang and Yan, Jin and Li, Hangyue and Ding, Rengen and Lall, Amrita and Rabiei, Afsaneh and Bowen, Paul}, year={2020}, pages={12955–12969} }
 @article{marx_portanova_rabiei_2020, title={Performance of Composite Metal Foam Armors against Various Threat Sizes}, volume={4}, ISSN={["2504-477X"]}, DOI={10.3390/jcs4040176}, abstractNote={The ballistic capabilities of composite metal foam (CMF) armors were experimentally tested against a 14.5 × 114 mm B32 armor-piercing incendiary (API) and compared to various sizes of armor-piercing (AP) ballistic threats, ranging from a 7.62 to 12.7 mm. Three different arrangements of layered hard armors were designed and manufactured using ceramic faceplates (in one layer, two layers or multiple tiles), a combination of ceramic and steel face sheets, with a single-layered CMF core, and a thin aluminum backing. The performance of various CMF armor designs against the 14.5 mm rounds are compared to each other and to the performance of the rolled homogeneous armor standard to identify the most efficient design for further investigations. The percentage of kinetic energy absorbed by the CMF layer in various armor arrangements and in tests against various threat sizes was calculated and compared. It appears that the larger the threat size, the more efficient the CMF layer will be due to a greater number of hollow metal spheres that are engaged in absorbing the impact energy. The results from this study will help to model and predict the performance of CMF armors against various threat sizes and impact energies.}, number={4}, journal={JOURNAL OF COMPOSITES SCIENCE}, author={Marx, Jacob and Portanova, Marc and Rabiei, Afsaneh}, year={2020}, month={Dec} }
 @article{marx_robbins_grady_palmieri_wohl_rabiei_2020, title={Polymer infused composite metal foam as a potential aircraft leading edge material}, volume={505}, ISSN={["1873-5584"]}, DOI={10.1016/j.apsusc.2019.144114}, abstractNote={The leading edge of aircraft wings must be free from three-dimensional disturbances caused by insect adhesion, ice accretion, and particle wear in order to improve flight performance, safety, and fuel efficiency of the aircraft. An innovative solution was explored in this work by infusing stainless steel composite metal foam (S-S CMF) with a hydrophobic epoxy resin system. S-S CMF was made with 100% stainless steel using a powder metallurgy technique. The infused epoxy filled the macro- and microporosities, unique to S-S CMF’s structure, creating a product with a density similar to that of aluminum. The contact angle, wear rate, erosion resistance, and insect adhesion of the novel infused composite metal foam were measured and compared to aluminum, epoxy and stainless steel. The infusion process was determined to fill up to 88% of the pores within the S-S CMF and was found to reduce wettability and insect residue accretion. The contact angle of the infused S-S CMF was 43% higher than its parent material, stainless steel, and 130% higher than aluminum. Insect residue maximum height and areal coverage were reduced by 60 and 30%, respectively, compared to aluminum. Grit blast experiments to simulate erosion resulted in a greater roughness increase for aluminum than for the parent epoxy resin or the resin-infused S-S CMF. These results suggest that the durability and performance of infused S-S CMF was superior compared to aluminum, which is the current leading edge material of choice. Based on the promising results under relevant wear and erosion conditions, it is concluded that the infused S-S CMF can offer a potential tailored replacement to aluminum leading edge material.}, journal={APPLIED SURFACE SCIENCE}, author={Marx, Jacob C. and Robbins, Samuel J. and Grady, Zane A. and Palmieri, Frank L. and Wohl, Christopher J. and Rabiei, Afsaneh}, year={2020}, month={Mar} }
 @article{rabiei_karimpour_basu_janssens_2020, title={Steel-steel composite metal foam in simulated pool fire testing}, volume={153}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2020.106336}, abstractNote={A comprehensive experimental and numerical simulated pool fire test is conducted on stainless steel composite metal foam (S–S CMF) panels and is reported in this study. The uncertainty assessments for the measured and calculated unexposed surface temperatures in the calibration and simulated pool fire tests on the S–S CMF specimens are also conducted and reported. This test procedure is designed to measure the thermal performance of new or untried thermal protection systems, such as S–S CMF, and to test for its survivability when exposed to a 100-min pool fire condition. The assembly was tested in triplicate in three consecutive simulated pool-fire exposures as specified in 49 CFR Part 179, Appendix B and achieved successful results. Based on the experimental and modeling results as well as the uncertainty studies, the 15.9 mm thick steel-steel composite metal foams tested as a novel insulation system met the acceptance criteria for the simulated pool fire test specified in 49 CFR 179 Appendix B by a large margin and is expected to pass with near certainty if the test were to be reproduced in a different laboratory. The main reason for successful performance of S–S CMF is attributed to the large air content in the material. The numerical studies reported in this study indicated that the low surface emissivity of the material is also contributing to the superior performance of the material to some extent. To complete the full test requirements of CFR Part 179 App. B, the material will need to be tested against the torch-fire exposure in duplicate. This research indicates that one of the potential applications of lightweight S–S CMF can be in tank cars carrying hazardous materials and replacing conventional structural steel with demonstrated benefits of excellent thermal insulation, fire resistance, low weight along with its established energy absorption capabilities.}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Rabiei, A. and Karimpour, K. and Basu, D. and Janssens, M.}, year={2020}, month={Jul} }
 @article{marx_rabiei_2020, title={Study on the Microstructure and Compression of Composite Metal Foam Core Sandwich Panels}, volume={51}, ISSN={["1543-1940"]}, DOI={10.1007/s11661-020-05964-1}, number={10}, journal={METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE}, author={Marx, Jacob and Rabiei, Afsaneh}, year={2020}, month={Oct}, pages={5187–5197} }
 @article{marx_portanova_rabiei_2019, title={Ballistic performance of composite metal foam against large caliber threats}, volume={225}, ISSN={["1879-1085"]}, DOI={10.1016/j.compstruct.2019.111032}, abstractNote={The goal of this study is to investigate the effectiveness of Composite Metal Foam (CMF) armors against 0.50 caliber ballistic threats. A hard armor was manufactured using a sandwich panel construction consisting of a ceramic faceplate, a CMF core, and a thin aluminum back plate. The hard armor system was tested against 0.50 caliber (12.7 × 99 mm) ball and armor piercing (AP) rounds. The CMF armors were tested with a variety of areal densities at impact velocities between 500 and 885 m/s. The armors stopped the threats at speeds up to 819 m/s without penetration. The CMF layer was found to absorb 73–76% and 69–79% of the kinetic energy of the ball and AP round respectively. When compared to rolled homogeneous steel armor (RHA), the CMF hard armors, in their current unoptimized condition, have a mass efficiency ratio of approximately 2.1. The CMF armor offers a much needed weight savings without sacrificing protection. Finite element analysis was completed using ANSYS/AUTODYN Explicit Dynamics solver to study the material interactions and impact. The results are shown to be in good agreement with the experimental findings.}, journal={COMPOSITE STRUCTURES}, author={Marx, Jacob and Portanova, Marc and Rabiei, Afsaneh}, year={2019}, month={Oct} }
 @article{ding_yan_li_yu_rabiei_bowen_2019, title={Deformation microstructure and tensile properties of Alloy 709 at different temperatures}, volume={176}, ISSN={["1873-4197"]}, DOI={10.1016/j.matdes.2019.107843}, abstractNote={Alloy 709 austenitic stainless steel is being investigated as a candidate structural material for the next generation fast neutron reactors at service temperature of 500–550 °C. However, the study of deformation mechanisms on Alloy 709 and of tensile response of aged Alloy 709 is lacking. In this study, thus, the tensile behaviour of as-received and aged Alloy 709, their deformation microstructures and failure mechanisms, have been investigated at room temperature (RT), 550, 650 and 750 °C. Aging brought about the formation of particles at grain boundaries and interior of grain, thus leading to enhancement of yield strength but reduction in ductility. The ultimate strength of both materials is strongly temperature dependent, which clearly decreases with temperature. It is caused by the decreasing strain hardening ability, dynamic strain aging and dynamic recovery together with dynamic recrystallisation at different temperatures.}, journal={MATERIALS & DESIGN}, author={Ding, Rengen and Yan, Jin and Li, Hangyue and Yu, Suyang and Rabiei, Afsaneh and Bowen, Paul}, year={2019}, month={Aug} }
 @article{ding_yan_li_yu_rabiei_bowen_2019, title={Microstructural evolution of Alloy 709 during aging}, volume={154}, ISSN={["1873-4189"]}, DOI={10.1016/j.matchar.2019.06.018}, abstractNote={The creep-resistant austenitic stainless steel Alloy 709 (Fe-20Cr-25Ni (wt%) based steel) is being investigated as a candidate structural material for the next generation fast neutron reactors at service temperature of 500–550 °C. However, the study of microstructural evolution of Alloy 709 during aging is lacking. In this study, thus, the microstructure of Alloy 709 has been investigated using electron microscopy in the as-received state and after static aging at 550, 650 and 750 °C. The results show that the prominent precipitate in the as-received Alloy 709 is Nb(CN), with the rod-like Z phase (CrNbN) observed very occasionally. After aging at 550 °C even up to 2000 h, no significant microstructure change was observed, which means that Alloy 709 is fairly stable at 550 °C. Aging at 650 °C produced globular M23C6 phase on grain boundaries, plate-like M23C6 carbides at twin boundaries and in the grain interior, and blocky M23C6 carbide nucleated on Nb(CN). Fine dispersoid Z phases were found on dislocations after aging at 650 °C for 500 h; their amount increases with aging time and temperature. (Cr,Mo)3(Ni,Fe)2SiN θ phase forms at grain boundaries after aging at 650 °C for 1000 h. After aging at 750 °C, θ phase nucleated on M23C6 carbide and a transformation of M23C6 to θ phase was found, which suggests that θ phase is the more stable. Aging at 550 °C promotes the segregation of Cr and Mo to grain boundaries whereas clear Cr depletion was observed at 650 °C due to the precipitation of Cr-rich M23C6 carbides at grain boundaries. Such depletion nearly disappears at 750 °C. The implications of aging for the subsequent mechanical behaviour of Alloy 709 are discussed briefly.}, journal={MATERIALS CHARACTERIZATION}, author={Ding, Rengen and Yan, Jin and Li, Hangyue and Yu, Suyang and Rabiei, Afsaneh and Bowen, Paul}, year={2019}, month={Aug}, pages={400–423} }
 @article{lall_sarkar_ding_bowen_rabiei_2019, title={Performance of Alloy 709 under creep-fatigue at various dwell times}, volume={761}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2019.138028}, abstractNote={A comprehensive experimental evaluation of the creep-fatigue behavior of Alloy 709 at 750 °C is reported in this study. Alloy 709 is a 20Cr–25Ni austenitic stainless steel, with high temperature creep strength and corrosion resistance, which can potentially be used in structural components of nuclear power plants. Creep-fatigue crack growth (CFCG) experiments were conducted using an in-situ heating-loading and Scanning Electron Microscope (SEM) equipped with Electron Backscatter Diffraction (EBSD) detector. To study the "real-time" CFCG behavior of Alloy 709 at 750 °C with varying dwell times in vacuum, flat dog bone samples were prepared. A starter notch was added, and a pre-crack was introduced by high frequency fatigue cycles at room temperature. Prior to loading and heating the entire area ahead of the crack tip was mapped using EBSD. These maps were utilized to generate a set of Coincident Site Lattice (CSL) boundary maps from the area ahead of the crack tip. Upon completion of the EBSD and CSL mapping, the heating and loading of samples took place in the SEM. During the experiment, crack growth was monitored on the surface of the sample using SEM imaging and data was transferred over to the CSL maps, to highlight the crack path with respect to the grain boundary and precipitations arrangement in the sample. Some samples went through EBSD-CSL mapping before heating and loading along with Transmission Electron Microscopy (TEM) imaging post heating and loading. Comparing the CSL maps before and after crack growth provided additional details about the dependence of crack path and crack growth mode on microstructure, primarily grain boundary character, and dwell time. TEM analysis of the microstructure after the crack growth was employed to validate the findings of the in-situ heating and loading SEM data. Real-time monitoring of microstructural phenomena, such as void nucleation, grain boundary cavitation, slip activation, and resistance of twin boundaries to cracking during CFCG tests, sheds a new light on the crack growth mechanism. The results indicated that at lower dwell times, the crack mainly propagates in a transgranular fashion, with the aid of slip lines. At higher dwell time, intergranular cavitation dominates the crack growth. However, as more than 50% of grain boundaries are coherent twin boundaries, which are low energy boundaries resistant to cavitation, crack growth is delayed when reaching such boundaries and hence twin boundaries impart some resistance to crack propagation in Alloy 709 at high temperatures.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Lall, Amrita and Sarkar, Siddhartha and Ding, Rengen and Bowen, Paul and Rabiei, Afsaneh}, year={2019}, month={Jul} }
 @article{marx_portanova_rabiei_2018, title={A study on blast and fragment resistance of composite metal foams through experimental and modeling approaches}, volume={194}, ISSN={["1879-1085"]}, DOI={10.1016/j.compstruct.2018.03.075}, abstractNote={Composite metal foam (CMF) is known for its high strength to density ratio and extraordinary energy absorption capabilities. In this study, stainless steel CMF panels are manufactured and tested against high explosive incendiary (HEI) rounds to study their resistance against explosive blast pressure and the resulting fragments. It is shown that the CMF panels were able to stop the imparted fragments of various sizes, with speeds up to 1500 m/s, and absorb the blast energy without cracking or bowing. The experimental findings were verified using IMPETUS Afea Solver and compared to the performance of a conventional aluminum armor. It is observed that despite their similar mass, the depth of penetration of the fragments into the aluminum plate is higher than that of the CMF panel. Significant front petaling and bulging is observed in aluminum plate following impact of the blast and frags. No petaling and minimal bulging is observed in all CMF panels. In addition, CMF panels are far less stressed when compared to the aluminum plate at any interval following the blast. The experimental and analytical results prove that novel CMF material can be the solution for the pressing need for effective light-weight vehicular armors.}, journal={COMPOSITE STRUCTURES}, author={Marx, Jacob and Portanova, Marc and Rabiei, Afsaneh}, year={2018}, month={Jun}, pages={652–661} }
 @article{upadhayay_li_bowen_rabiei_2018, title={A study on tensile properties of Alloy 709 at various temperatures}, volume={733}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2018.06.089}, abstractNote={In recent years, there have been several advancements in energy production from both fossil fuels and the alternate “clean” sources such as nuclear fission. These advancements are fueled by the need for more efficient systems that will optimize the use of the depleting fossil fuel reserves and shift the focus to cleaner sources of energy. The efficiency of any power generation cycle is dependent on the ability of the structural material to withstand increased peak operating temperatures. Advanced austenitic stainless steels have been in the focus as structural material for the next generation nuclear power plants, due to their strength, corrosion resistance, weldability and the wide range of temperatures at which the austenite phase is stable. Alloy 709, a recently developed advanced austenitic stainless steel, is being investigated in this paper. In this study, tensile tests were conducted on dog-bone samples of Alloy 709 in an in-situ scanning electron microscope (SEM) loading and heating stage, equipped with electron backscatter diffraction (EBSD), at various temperatures. The in-situ experiments indicated that the material primarily accommodated deformation by slip at lower temperatures. Void formation and coalescence at grain boundaries preceded slip at higher temperatures. Although crack initiation at all elevated temperatures was intergranular, the crack propagation through the material and the final fracture was transgranular ductile. Additionally, tensile tests were conducted on larger cylindrical samples at 550, 650 and 750 °C in air. The results of tests conducted in air and in-situ were found to be in agreement, at these temperatures.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Upadhayay, Swathi and Li, Hangyue and Bowen, Paul and Rabiei, Afsaneh}, year={2018}, month={Aug}, pages={338–349} }
 @article{marx_rabiei_2017, title={Overview of Composite Metal Foams and Their Properties and Performance}, volume={19}, ISSN={1438-1656}, url={http://dx.doi.org/10.1002/adem.201600776}, DOI={10.1002/adem.201600776}, abstractNote={This paper reviews the background and evolution of composite metal foam (CMF) from its inception until now. A broad understanding of the processing and basic mechanical, microstructural, and physical properties of different types of composite metal foams is discussed in the first part of the paper. In the second part, some recent studies on high strain rate properties, ballistic performance, radiation attenuation, and thermal properties of composite metal foams are discussed and compared with other bulk and control materials. These properties suggest many potential applications for this novel material in a broad range of engineering structures from ballistic armors to trains', cars', buses', helicopters' crashworthiness systems, and many others such as nuclear casks and thermal insulating units.}, number={11}, journal={Advanced Engineering Materials}, publisher={Wiley}, author={Marx, Jacob and Rabiei, Afsaneh}, year={2017}, month={Mar}, pages={1600776} }
 @article{durham_allen_rabiei_2017, title={Preparation, characterization and in vitro response of bioactive coatings on polyether ether ketone}, volume={105}, ISSN={["1552-4981"]}, DOI={10.1002/jbm.b.33578}, abstractNote={Polyether ether ketone (PEEK) is a highly heat-resistant thermoplastic with excellent strength and elastic modulus similar to human bone, making it an attractive material for orthopedic implants. However, the hydrophobic surface of PEEK implants induces fibrous encapsulation which is unfavorable for stable implant anchorage. In this study, PEEK was coated via ion-beam-assisted deposition (IBAD) using a two-layer design of yttria-stabilized zirconia (YSZ) as a heat-protection layer, and hydroxyapatite (HA) as a top layer to improve osseointegration. Microstructural analysis of the coatings showed a dense, uniform columnar grain structure in the YSZ layer and no delamination from the substrate. The HA layer was found to be amorphous and free of porosities in its as-deposited state. Subsequent heat treatment via microwave energy followed by autoclaving crystallized the HA layer, confirmed by SEM and XRD analysis. An in vitro study using MC3T3 preosteoblast cells showed improved bioactivity in heat-treated sample groups. Cell proliferation, differentiation, and mineralization were analyzed by MTT assay and DNA content, osteocalcin expression, and Alizarin Red S (AR-S) content, respectively. Initial cell growth was increased, and osteogenic maturation and mineralization were accelerated most on coatings that underwent a combined microwave and autoclave heat treatment process as compared to uncoated PEEK and amorphous HA surfaces. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 560-567, 2017.}, number={3}, journal={JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS}, author={Durham, John W., III and Allen, Matthew J. and Rabiei, Afsaneh}, year={2017}, month={Apr}, pages={560–567} }
 @article{durham_rabiei_2016, title={Deposition, heat treatment and characterization of two layer bioactive coatings on cylindrical PEEK}, volume={301}, ISSN={["0257-8972"]}, DOI={10.1016/j.surfcoat.2015.12.045}, abstractNote={Polyether ether ketone (PEEK) rods were coated via ion beam asssisted deposition (IBAD) at room temperature. The coating consists of a two-layer design of yttria-stabilized zirconia (YSZ) as a heat-protection layer, and hydroxyapatite (HA) as a top layer to increase bioactivity. A rotating substrate holder was designed to deposit an even coating on the cylindrical surface of PEEK rods; the uniformity is verified by cross-sectional measurements using scanning electron microscopy (SEM). Deposition is followed by heat treatment of the coating using microwave annealing and autoclaving. Transmission electron microscopy (TEM) showed a dense, uniform columnar grain structure in the YSZ layer that is well bonded to the PEEK substrate, while the calcium phosphate layer was amorphous and pore-free in its as-deposited state. Subsequent heat treatment via microwave energy introduced HA crystallization in the calcium phosphate layer and additional autoclaving further expanded the crystallization of the HA layer. Chemical composition evaluation of the coating indicated the Ca/P ratios of the HA layer to be near that of stoichiometric HA, with minor variations through the HA layer thickness. The adhesion strength of as-deposited HA/YSZ coatings on smooth, polished PEEK surfaces was mostly unaffected by microwave heat treatment, but decreased with additional autoclave treatment. Increasing surface roughness showed improvement of bond strength.}, journal={SURFACE & COATINGS TECHNOLOGY}, author={Durham, John W., III and Rabiei, Afsaneh}, year={2016}, month={Sep}, pages={106–113} }
 @article{chen_marx_rabiei_2016, title={Experimental and computational studies on the thermal behavior and fire retardant properties of composite metal foams}, volume={106}, ISSN={["1778-4166"]}, DOI={10.1016/j.ijthermalsci.2016.03.005}, abstractNote={A comprehensive experimental and computational evaluation of thermal behavior and fire retardant properties of composite metal foams (CMFs) is reported in this study. Thermal behavior characterizations were carried out through specific heat, effective thermal conductivity, and coefficient of thermal expansion analyses using differential scanning calorimetry, high temperature guarded-comparative-longitudinal heat flow technique, and thermomechanical analyzer (TMA), respectively. The experimental results were compared with analytical results obtained from, respectively, rule of mixture, Brailsford and Major's model, and modified Turner's model for verification. United States Nuclear Regulatory Commission (USNRC) standards were employed as regulatory standards and criteria for fire retardant property study. The results revealed a superior thermal resistance and fire survivability of CMFs compared to 304L stainless steel. A physics-based three-dimensional model accounting for heat conduction was built using Finite Element Analysis to validate the reliability of the experimental results. The model led to a good reproduction of the experimentally measured data when comparing CMF to bulk stainless steel. This research indicates that one of the potential applications of lightweight CMFs can be in nuclear spent fuel casks replacing conventional structural and radiation shielding materials with demonstrated benefits of excellent thermal isolation, fire retardant, light weight and energy absorption capabilities.}, journal={INTERNATIONAL JOURNAL OF THERMAL SCIENCES}, author={Chen, Shuo and Marx, Jacob and Rabiei, Afsaneh}, year={2016}, month={Aug}, pages={70–79} }
 @article{durham_montelongo_ong_guda_allen_rabiei_2016, title={Hydroxyapatite coating on PEEK implants: Biomechanical and histological study in a rabbit model}, volume={68}, ISSN={["1873-0191"]}, DOI={10.1016/j.msec.2016.06.049}, abstractNote={A bioactive two-layer coating consisting of hydroxyapatite (HA) and yttria-stabilized zirconia (YSZ) was investigated on cylindrical polyetheretherketone (PEEK) implants using ion beam assisted deposition (IBAD). Post-deposition heat treatments via variable frequency microwave annealing with and without subsequent autoclaving were used to crystallize the as-deposited amorphous HA layer. Microstructural analysis, performed by TEM and EDS, showed that these methods were capable of crystallizing HA coating on PEEK. The in vivo response to cylindrical PEEK samples with and without coating was studied by implanting uncoated PEEK and coated PEEK implants in the lateral femoral condyle of 18 rabbits. Animals were studied in two groups of 9 for observation at 6 or 18weeks post surgery. Micro-CT analysis, histology, and mechanical pull-out tests were performed to determine the effect of the coating on osseointegration. The heat-treated HA/YSZ coatings showed improved implant fixation as well as higher bone regeneration and bone-implant contact area compared to uncoated PEEK. The study offers a novel method to coat PEEK implants with improved osseointegration.}, journal={MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS}, author={Durham, John W., III and Montelongo, Sergio A. and Ong, Joo L. and Guda, Teja and Allen, Matthew J. and Rabiei, Afsaneh}, year={2016}, month={Nov}, pages={723–731} }
 @article{rabiei_2016, title={Retraction notice to Processing, characterization and failure analysis of a novel thin sheet metal [Mater. Des. 86(2016) 752–760]}, volume={101}, ISSN={0264-1275}, url={http://dx.doi.org/10.1016/J.MATDES.2016.04.035}, DOI={10.1016/J.MATDES.2016.04.035}, journal={Materials & Design}, publisher={Elsevier BV}, author={Rabiei, Afsaneh}, year={2016}, month={Jul}, pages={366} }
 @article{chen_bourham_rabiei_2015, title={Attenuation efficiency of X-ray and comparison to gamma ray and neutrons in composite metal foams}, volume={117}, ISSN={["0969-806X"]}, DOI={10.1016/j.radphyschem.2015.07.003}, abstractNote={Steel–steel composite metal foams (S–S CMFs) and Aluminum–steel composite metal foams (Al–S CMFs) with various sphere sizes and matrix materials were manufactured and investigated for nuclear and radiation environments applications. 316 L Stainless steel, high-speed T15 steel and aluminum materials were used as the matrix material together with 2, 4 and 5.2 mm steel hollow spheres to manufacture various types of composite metal foams (CMFs). High-speed T15 steel is selected due to its high tungsten and vanadium concentration (both high-Z elements) to further improve the shielding efficiency of CMFs. This new type of S–S CMF is called high-Z steel–steel composite metal foam (HZ S–S CMF). Radiation shielding efficiency of all types of CMFs was explored for the attenuation of X-ray, gamma ray and neutron. The experimental results were compared with pure lead and Aluminum A356, and verified theoretically through XCOM and Monte Carlo Z-particle Transport Code (MCNP). It was observed that the radiation shielding effectiveness of CMFs is relatively independent of sphere sizes as long as the ratio of sphere-wall thickness to its outer-radius stays constant. However, the smaller spheres seem to be more efficient in general due to the fine fluctuation in the gray value profile of their 2D Micro-CT images. S–S CMFs and Al–S CMFs are respectively 275% and 145% more effective for X-ray attenuation than Aluminum A356. Compared to pure lead, CMFs show adequate attenuation with additional advantages of being lightweight and more environmentally friendly. The mechanical performance of HZ S–S CMFs under quasi-static compression was compared to that of other classes of S–S CMF. It is observed that the addition of high-Z elements to the matrix of CMFs improved their shielding against X-rays, low energy gamma rays and neutrons, while maintained their low density, high mechanical properties and high-energy absorption capability.}, journal={RADIATION PHYSICS AND CHEMISTRY}, author={Chen, Shuo and Bourham, Mohamed and Rabiei, Afsaneh}, year={2015}, month={Dec}, pages={12–22} }
 @article{garcia-avila_portanova_rabiei_2015, title={Ballistic performance of composite metal foams}, volume={125}, ISSN={["1879-1085"]}, DOI={10.1016/j.compstruct.2015.01.031}, abstractNote={The application of advance materials to manufacture hard armor systems has led to high performance ballistic protection. Due to its light-weight and high impact energy absorption capabilities, composite metal foams have shown good potential for applications as ballistic armor. A high-performance light-weight composite armor system has been manufactured using boron carbide ceramics as the strike face, composite metal foam processed by powder metallurgy technique as a bullet kinetic energy absorber interlayer, and aluminum 7075 or Kevlar™ panels as backplates with a total armor thickness less than 25 mm. The ballistic tolerance of this novel composite armor system has been evaluated against the 7.62 × 51 mm M80 and 7.62 × 63 mm M2 armor piercing projectiles according to U.S. National Institute of Justice (NIJ) standard 0101.06. The results showed that composite metal foams absorbed approximately 60–70% of the total kinetic energy of the projectile effectively and stopped both types of projectiles with less depth of penetration and backplate deformation than that specified in the NIJ 0101.06 standard guidelines. Finite element analysis was performed using Abaqus/Explicit to study the failure mechanisms and energy absorption of the armor system. The results showed close agreement between experimental and analytical results.}, journal={COMPOSITE STRUCTURES}, author={Garcia-Avila, Matias and Portanova, Marc and Rabiei, Afsaneh}, year={2015}, month={Jul}, pages={202–211} }
 @article{garcia-avila_rabiei_2015, title={Effect of Sphere Properties on Microstructure and Mechanical Performance of Cast Composite Metal Foams}, volume={5}, ISSN={["2075-4701"]}, DOI={10.3390/met5020822}, abstractNote={Aluminum-steel composite metal foams (Al-S CMF) are manufactured using steel hollow spheres, with a variety of sphere carbon content, surface roughness, and wall porosity, embedded in an Aluminum matrix through gravity casting technique. The microstructural and mechanical properties of the material were studied using scanning electron microscopy, energy dispersive spectroscopy, and quasi-static compressive testing. Higher carbon content and surface roughness in the sphere wall were responsible for an increase in formation of intermetallic phases which had a strengthening effect at lower strain levels, increasing the yield strength of the material by a factor of 2, while higher sphere wall porosity resulted in a decrease on the density of the material and improving its cushioning and ductility maintaining its energy absorption capabilities.}, number={2}, journal={METALS}, author={Garcia-Avila, Matias and Rabiei, Afsaneh}, year={2015}, month={Jun}, pages={822–835} }
 @article{alvandi-tabrizi_whisler_kim_rabiei_2015, title={High strain rate behavior of composite metal foams}, volume={631}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2015.02.027}, abstractNote={The mechanical properties of Composite Metal Foams (CMFs) under low speed loading conditions have been considered in a number of studies. This paper aims to extend the current knowledge by investigating the compressive behavior of CMF under higher loading rates. Hopkinson bar experiment was conducted on samples processed through powder metallurgy and casting techniques. The effect of loading rate, sample geometry and sphere size on the mechanical properties and energy absorption capacity was studied. The obtained results reveal that increasing the loading rate improves the strength of CMF especially at strain levels below 30%. This strengthening due to high strain rate loading is mostly attributed to the strain rate sensitivity of the parent metals and the pressurization of the entrapped air inside the spheres.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Alvandi-Tabrizi, Y. and Whisler, D. A. and Kim, H. and Rabiei, A.}, year={2015}, month={Apr}, pages={248–257} }
 @article{chen_bourham_rabiei_2015, title={Neutrons attenuation on composite metal foams and hybrid open-cell Al foam}, volume={109}, ISSN={["0969-806X"]}, DOI={10.1016/j.radphyschem.2014.11.003}, abstractNote={A comprehensive investigation of monochromatic neutron attenuation effectiveness for close-cell composite metal foams (CMFs) and open-cell Al foam infiltrated with variety of second phase materials is presented using both experimental and theoretical methods. The experimental results indicated higher neutron flux reduction in open-cell Al foam with fillers compared to the close-cell CMFs due to their large percentage of low Z elements such as hydrogen, boron and carbon, with superior neutron attenuation performance, in their filler materials. The main factor controlling the shielding effectiveness of steel–steel CMFs is found to be the ratio of the thickness of the sphere wall to the sphere radius while the intermetallic phases in the matrix of Al–steel CMFs seem to have a major role on their shielding properties. Successful models that link the observed material properties and microstructure have been developed using Monte Carlo N-Particle Transport Code (MCNP) to verify the accuracy of the experimental results. Close-cell CMFs were proposed through three different sphere arrangements: simple cubic, body center cubic and face center cubic, whereas open-cell Al foam with fillers was represented by creating a three-dimensional structure using periodic unit cell through two approaches. The simulation results were found to be in good agreement with the experimental values. This research indicates the potential of utilizing light-weight close-cell CMFs and open-cell Al foam with fillers as nuclear shields replacing conventional materials to achieve a specified shielding level with additional benefits of excellent energy absorption and thermal isolation.}, journal={RADIATION PHYSICS AND CHEMISTRY}, author={Chen, Shuo and Bourham, Mohamed and Rabiei, Afsaneh}, year={2015}, month={Apr}, pages={27–39} }
 @article{rabiei_2015, title={Processing, characterization and failure analysis of a novel thin sheet metal (Retracted article. See vol. 101, pg. 366, 2016)}, volume={86}, ISSN={["1873-4197"]}, DOI={10.1016/j.matdes.2015.07.028}, abstractNote={This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The article has been retracted at the request of the author. The author made a request to add a co-author at the proof-reading stage. This was declined by the Journal in accordance to its policies laid out in the Guide for Authors. Accordingly, the author requested to retract this paper.}, journal={MATERIALS & DESIGN}, author={Rabiei, Afsaneh}, year={2015}, month={Dec}, pages={752–760} }
 @book{rabiei_2014, title={8th International Conference on Porous Metals and Metallic Foams}, volume={4}, journal={Procedia - Materials Science}, publisher={Elseiver}, year={2014} }
 @article{chen_bourham_rabiei_2014, title={Applications of Open-cell and Closed-cell Metal Foams for Radiation Shielding}, volume={4}, ISSN={2211-8128}, url={http://dx.doi.org/10.1016/j.mspro.2014.07.560}, DOI={10.1016/j.mspro.2014.07.560}, abstractNote={A comparison of attenuation effectiveness against gamma rays and thermal neutrons among aluminum A356, close-cell composite metal foams and open-cell Aluminum foam infiltrated with variety of second phase materials were investigated experimentally and theoretically in this study. Gamma rays attenuation measurements were carried out at photon energies of 0.060, 1.173, and 1.332 MeV and thermal neutron transmission measurements were conducted at North Carolina State University using PLUSTAR Neutron Powder Diffraction Facility with a thermal neutron flux of about 0.5x105n/cm2/s at the specimen location. The results obtained revealed that close-cell composite metal foams offer better gamma rays and neutron attenuation capabilities compared to aluminum A356, whereas open-cell Al foam with fillers exhibit higher neutron attenuation effectiveness than close-cell composite metal foams but less gamma rays shielding property than that of aluminum A356. This study indicates the potential of utilizing the light-weight composite metal foams as shielding material replacing current heavy materials used for attenuation of gamma rays and thermal neutrons with additional advantages such as high energy absorption and excellent heat rejection capabilities.}, journal={Procedia Materials Science}, publisher={Elsevier BV}, author={Chen, Shuo and Bourham, Mohamed and Rabiei, Afsaneh}, year={2014}, pages={293–298} }
 @article{garcia-avila_portanova_rabiei_2014, title={Ballistic Performance of a Composite Metal Foam-ceramic Armor System}, volume={4}, ISSN={2211-8128}, url={http://dx.doi.org/10.1016/j.mspro.2014.07.571}, DOI={10.1016/j.mspro.2014.07.571}, abstractNote={Composite Metal Foam is a low-weight, high-strength porous material capable of absorbing great amounts of energy under loading. In this report, Composite Metal Foam panels are manufactured using powder metallurgy technique and 2 mm steel hollow spheres in a steel matrix and used in conjunction with a ceramic plate to fabricate a new light-weight composite armor system. This armor system is tested under ballistic loading using 7.62x51 mm M80 and 7.62x63 mm M2 AP projectiles at varying impact velocities for single and multi-impact scenarios. The material behavior, failure mechanism, and ballistic performance of the armor system are studied for optimization.}, journal={Procedia Materials Science}, publisher={Elsevier BV}, author={Garcia-Avila, Matias and Portanova, Marc and Rabiei, Afsaneh}, year={2014}, pages={151–156} }
 @article{miao_rabiei_2014, title={Introduction of a New Type of Metal Foam (Metallic Bubble Wrap)}, volume={4}, ISSN={2211-8128}, url={http://dx.doi.org/10.1016/j.mspro.2014.07.563}, DOI={10.1016/j.mspro.2014.07.563}, abstractNote={New type of metallic foam is processed in the form of thin sheet aluminum with longer lifetime and more reliable properties than currently used metal foams. The current closed cell metallic foams are highly porous and non-uniform and their deformation behavior is not predictable, particularly in a thin sheet form. The new material has combined rolling technique with careful placement of foaming agent to produce thin sheet metal foams (a metallic version of bubble wraps) with regular pore structure and possibility of further addition of reinforcement. Both tension test results and bending test results show improvements in mechanical properties of aluminum bubble wrap.}, journal={Procedia Materials Science}, publisher={Elsevier BV}, author={Miao, Di and Rabiei, Afsaneh}, year={2014}, pages={3–7} }
 @article{chen_bourham_rabiei_2014, title={Novel light-weight materials for shielding gamma ray}, volume={96}, DOI={10.1016/j.radphyschem.2013.08.001}, abstractNote={A comparison of gamma ray attenuation effectiveness of bulk aluminum, close-cell composite metal foams and open-cell aluminum foam infiltrated with variety of second phase materials were investigated and reported in this study. Mass attenuation coefficients for six sets of samples with three different areal densities of 2, 5 and 10 g/cm2 were determined at photon energies of 0.060, 0.662, 1.173, and 1.332 MeV. Theoretical values were calculated using XCOM software package. A complete agreement was observed between experimental and theoretical results. It is observed that close-cell composite metal foams exhibit a better shielding capability compared to open-cell Al foam with fillers. It is also observed that close-cell composite metal foams offer superior shielding effectiveness compared to bulk aluminum for energies below 0.662 MeV, the mass attenuation coefficients of steel–steel composite metal foam and Al–steel composite metal foam were measured 400 and 300% higher than that of aluminum A356. This study indicates the potential of utilizing the light-weight composite metal foams as shielding material replacing current heavy materials used for attenuation of low energy gamma ray with additional advantages such as high energy absorption and excellent heat rejection capabilities.}, journal={Radiation Physics and Chemistry}, author={Chen, S. and Bourham, Mohamed and Rabiei, A.}, year={2014}, pages={27–37} }
 @article{rabiei_2014, title={Preface}, volume={4}, ISSN={2211-8128}, url={http://dx.doi.org/10.1016/J.MSPRO.2014.07.552}, DOI={10.1016/J.MSPRO.2014.07.552}, journal={Procedia Materials Science}, publisher={Elsevier BV}, author={Rabiei, Afsaneh}, year={2014}, pages={1} }
 @article{alvandi-tabrizi_rabiei_2014, title={Use of Composite Metal Foam for Improving Absorption of Collision Forces}, volume={4}, ISSN={2211-8128}, url={http://dx.doi.org/10.1016/j.mspro.2014.07.577}, DOI={10.1016/j.mspro.2014.07.577}, abstractNote={Studies devoted to understand the mechanical behavior of Composite Metal Foams (CMFs) have revealed superior energy absorption capacity under quasi-static loading. Accordingly, CMF is a great nominee to replace currently used materials in vehicles crash energy management system. However, in order to utilize the full capacity of CMF under impact loading, understanding its high strain rate behavior is needed. This paper seeks to investigate the strain rate sensitivity of CMF by conducting Split Hopkinson Pressure Bar experiments. The test samples were manufactured using powder metallurgy technique and the role of loading rate and sample size was studied. The obtained results shows high rate dependency of the stress-strain behavior and an improvement in energy absorption capacity under impact loading.}, journal={Procedia Materials Science}, publisher={Elsevier BV}, author={Alvandi-Tabrizi, Youness and Rabiei, Afsaneh}, year={2014}, pages={377–382} }
 @article{rabiei_garcia-avila_2013, title={Effect of various parameters on properties of composite steel foams under variety of loading rates}, volume={564}, ISSN={["0921-5093"]}, DOI={10.1016/j.msea.2012.11.108}, abstractNote={Steel–steel composite metal foams (CMF) are manufactured using steel hollow spheres (with variety of different sphere sizes, surface roughness and carbon content) embedded in a stainless steel matrix through powder metallurgy technique and are investigated experimentally under compression loading with variety of loading rates. The microstructural and mechanical properties of the material were studied using optical and scanning electron microscopy, energy dispersive spectroscopy, quasi-static, and dynamic compressive loading up to 26 m/s. It is observed that the yield and plateau strength as well as the energy absorption capabilities of the composite foams are increased with increasing loading rate and by decreasing sphere sizes. Such mechanical properties improved by additional carbon content in the sphere wall at strains below 17% while the effect of density, resulted from porosity content, showed an improvement on the densification strain and plateau strengths at higher than 17% strain. The effect of spheres surface roughness and carbon content on mechanical properties of CMF seemed to be minimal compared to other parameters. As a result, the features controlling the life time and performance of composite metal foams under static and dynamic loading have been categorized into two main groups. The first group that controls the yield and plateau strength of the foam at lower strain levels includes bonding strength between the spheres and matrix which is a function of the sphere surface roughness and the gradient chemical composition between the spheres and matrix. The second group that controls the relative density, densification strain and plateau strength at higher strain levels belongs to the sphere diameter and the porosity content in both spheres and matrix. Moreover, increasing the loading rate improves the yield strength of all CMF samples.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Rabiei, Afsaneh and Garcia-Avila, Matias}, year={2013}, month={Mar}, pages={539–547} }
 @book{rabiei_2013, place={Basel, Switzerland}, title={Metal Foams 2013}, volume={3}, ISSN={2075-4701}, number={Special Issue}, journal={Metals}, publisher={MDPI.}, year={2013} }
 @article{rabiei_sandukas_2013, title={Processing and evaluation of bioactive coatings on polymeric implants}, volume={101}, ISSN={["1552-4965"]}, DOI={10.1002/jbm.a.34557}, abstractNote={Polyetheretherketone (PEEK) is a high‐performance polymer with advantages over metallic biomaterials for application in spinal implants. In this study, hydroxyapatite (HA) coatings were deposited onto PEEK substrates using radio‐frequency magnetron sputtering for the purpose of improving bioactivity. An intermediate coating layer of yttria‐stabilized zirconia (YSZ) was first deposited onto the PEEK substrates to provide heat shielding during subsequent post‐deposition heat treatment to prevent degradation of PEEK substrates and coating/substrate interface. Plasma activation of the PEEK substrate surfaces before deposition resulted in a significant increase in coating adhesion strength. Post‐deposition heat treatments of microwave and hydrothermal annealing were studied with the goal of forming crystalline HA without the use of high temperatures required in conventional annealing. Microstructural and compositional analyses by scanning electron microscopy (SEM) and X‐ray diffraction revealed that the YSZ layer exhibited a crystalline structure as‐deposited, with columnar grains oriented along the growth direction, whereas the HA layer was shown to be amorphous as‐deposited. After microwave annealing, the HA coating exhibited a columnar crystalline microstructure, similar to that of the underlying YSZ crystalline layer; XRD analysis confirmed a crystalline HA phase in the coating. It is suggested that the existence of the crystalline YSZ layer aids in the formation of the HA layer upon heating, possibly lowering the activation energy for crystallization by providing nucleation sites for HA grain formation. Cell culture tests showed a significant increase in initial cell attachment and growth on the microwave‐annealed coatings, compared with uncoated PEEK and amorphous HA surfaces. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 2621–2629, 2013.}, number={9}, journal={JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A}, author={Rabiei, Afsaneh and Sandukas, Stefan}, year={2013}, month={Sep}, pages={2621–2629} }
 @article{bai_sandukas_appleford_ong_rabiei_2012, title={Antibacterial effect and cytotoxicity of Ag-doped functionally graded hydroxyapatite coatings}, volume={100B}, ISSN={["1552-4981"]}, DOI={10.1002/jbm.b.31985}, abstractNote={Abstract}, number={2}, journal={JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS}, author={Bai, Xiao and Sandukas, Stefan and Appleford, Mark and Ong, Joo L. and Rabiei, Afsaneh}, year={2012}, month={Feb}, pages={553–561} }
 @article{vendra_brown_rabiei_2011, title={Effect of processing parameters on the microstructure and mechanical properties of Al-steel composite foam}, volume={46}, ISSN={["1573-4803"]}, DOI={10.1007/s10853-011-5356-4}, number={13}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Vendra, L. J. and Brown, J. A. and Rabiei, A.}, year={2011}, month={Jul}, pages={4574–4581} }
 @article{sandukas_yamamoto_rabiei_2011, title={Osteoblast adhesion to functionally graded hydroxyapatite coatings doped with silver}, volume={97A}, ISSN={["1552-4965"]}, DOI={10.1002/jbm.a.33081}, abstractNote={Abstract}, number={4}, journal={JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A}, author={Sandukas, Stefan and Yamamoto, Akiko and Rabiei, Afsaneh}, year={2011}, month={Jun}, pages={490–497} }
 @article{xu_bourham_rabiei_2010, title={A novel ultra-light structure for radiation shielding}, volume={31}, ISSN={["1873-4197"]}, DOI={10.1016/j.matdes.2009.11.011}, abstractNote={A new ultra-light structure based on the application of open-cell metal foams has been designed and investigated to determine its ability for attenuation of γ-rays and thermal neutrons. Open-cell metal foam, a unique class of material, has been employed in the structure and is studied in this work where radiation attenuation abilities of foams and foams filled with water and borated water have been compared with bulk Aluminum. The γ-ray attenuation measurements were performed using γ-ray at 0.662, 1.173 and 1.332 MeV photon energies and thermal neutron attenuation measurements were conducted using a polyenergetic thermal neutron beam. The results show that the metallic foam by itself attenuates less γ-ray as compared to bulk material, while the mass attenuation coefficients of foams filled with water is higher than that of bulk metals. The thermal neutron experiment, on the other hand, has shown a dramatic attenuation improvement in foams filled with water and particularly with borated water as compared to bulk metal and foam.}, number={4}, journal={MATERIALS & DESIGN}, author={Xu, Siqi and Bourham, Mohamed and Rabiei, Afsaneh}, year={2010}, month={Apr}, pages={2140–2146} }
 @article{brown_vendra_rabiei_2010, title={Bending Properties of Al-Steel and Steel-Steel Composite Metal Foams}, volume={41A}, ISSN={["1543-1940"]}, DOI={10.1007/s11661-010-0343-y}, number={11}, journal={METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE}, author={Brown, Judith A. and Vendra, Lakshmi J. and Rabiei, Afsaneh}, year={2010}, month={Nov}, pages={2784–2793} }
 @misc{rabiei_2010, title={Composite metal foam and methods of preparation thereof}, volume={7,641,984}, number={2010 Jan. 5}, author={Rabiei, A.}, year={2010} }
 @article{vendra_rabiei_2010, title={Evaluation of modulus of elasticity of composite metal foams by experimental and numerical techniques}, volume={527}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2009.11.004}, abstractNote={The elastic behavior of Al–steel composite metal foams developed by casting technique was characterized by evaluating the modulus of elasticity through compression experiments, constitutive scaling equations and 2D finite element modeling. Experiments showed an elastic modulus of 10–12 GPa for Al–steel composite foams while the scaling laws predicted 3.5 GPa and 30 GPa as the lower and upper bounds of modulus of elasticity respectively. Two-dimensional finite element models of composite foams developed and analyzed assuming perfectly elastic materials, resulted in an elastic modulus of 10 GPa which is in good agreement with the experimental results.}, number={7-8}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Vendra, L. and Rabiei, A.}, year={2010}, month={Mar}, pages={1784–1790} }
 @article{bai_more_rouleau_rabiei_2010, title={Functionally graded hydroxyapatite coatings doped with antibacterial components}, volume={6}, ISSN={["1878-7568"]}, DOI={10.1016/j.actbio.2009.12.002}, abstractNote={A series of functionally graded hydroxyapatite (FGHA) coatings incorporated with various percentages of silver were deposited on titanium substrates using ion beam-assisted deposition. The analysis of the coating's cross-section using transmission electron microscopy (TEM) and scanning transmission electron microscopy equipped with energy dispersive X-ray spectroscopy has shown a decreased crystallinity as well as a distribution of nanoscale (10-50nm) silver particles from the coating/substrate interface to top surface. Both X-ray diffraction and fast Fourier transforms on high-resolution TEM images revealed the presence of hydroxyapatite within the coatings. The amount of Ag (wt.%) on the outer surface of the FGHA, as determined from X-ray photoelectron spectroscopy, ranged from 1.09 to 6.59, which was about half of the average Ag wt.% incorporated in the entire coating. Average adhesion strengths evaluated by pull-off tests were in the range of 83+/-6 to 88+/-3MPa, which is comparable to 85MPa for FGHA without silver. Further optical observations of failed areas illustrated that the dominant failure mechanism was epoxy failure, and FGHA coating delamination was not observed.}, number={6}, journal={ACTA BIOMATERIALIA}, author={Bai, Xiao and More, Karren and Rouleau, Christopher M. and Rabiei, Afsaneh}, year={2010}, month={Jun}, pages={2264–2273} }
 @article{rabiei_2010, title={Recent developments and the future of bone mimicking: materials for use in biomedical implants}, volume={7}, ISSN={["1743-4440"]}, DOI={10.1586/erd.10.51}, abstractNote={There are 206 bones in the human skeleton (excluding teeth) that provide shape and support for the body, act as levers for muscles, and protect vital organs. When a bone has been badly damaged from any cause, such as arthritis, malformation since birth or abnormal development and damage from injury, a bone replacement would become necessary to restore function to the human body. Although the history of using man-made materials to replace a human’s hard tissues such as bone and teeth goes back to 2700 BC, where ancient civilizations used gold in dentistry, the actual development of man-made material as bone replacement has only happened within the past 100 years [1]. In order to have a good hard tissue replacement in the body, we need a material with the following requirements:}, number={6}, journal={EXPERT REVIEW OF MEDICAL DEVICES}, author={Rabiei, Afsaneh}, year={2010}, month={Nov}, pages={727–729} }
 @article{rabiei_vendra_2009, title={A comparison of composite metal foam's properties and other comparable metal foams}, volume={63}, ISSN={["1873-4979"]}, DOI={10.1016/j.matlet.2008.11.002}, abstractNote={New closed cell composite metal foams are processed using casting and powder metallurgy (PM) techniques. The foam is comprised of steel hollow spheres packed into a random loose arrangement, with the interstitial spaces between spheres occupied with a solid metallic matrix. The characterization of composite metal foams was carried out using monotonic compression, compression–compression fatigue, loading–unloading compression, micro-hardness and nano-hardness testing. The microstructure of the composite metal foams was studied using optical, scanning electron microscopy imaging and electron dispersive spectroscopy. The composite metal foams displayed superior (5–20 times higher) compressive strengths, reported as 105 MPa for cast foams and 127 MPa for PM foams, and much higher energy absorbing capability as compared to other metal foams being produced with similar materials through other technologies.}, number={5}, journal={MATERIALS LETTERS}, author={Rabiei, A. and Vendra, L. J.}, year={2009}, month={Feb}, pages={533–536} }
 @book{narayan_2009, place={Boston, MA}, title={Biomedical Materials}, ISBN={9780387848716 9780387848723 9781489983114}, url={http://dx.doi.org/10.1007/978-0-387-84872-3}, DOI={10.1007/978-0-387-84872-3}, publisher={Springer US}, year={2009} }
 @article{bai_sandukas_appleford_ong_rabiei_2009, title={Deposition and investigation of functionally graded calcium phosphate coatings on titanium}, volume={5}, ISSN={["1878-7568"]}, DOI={10.1016/j.actbio.2009.05.013}, abstractNote={A series of calcium phosphate coatings with graded crystallinity were deposited onto heated titanium substrates using ion beam assisted deposition. The microstructure of the coating was examined using transmission electron microscopy (TEM). The coating thickness was observed to be in a range of 594-694 nm. The degree of crystallinity and microstructural grain size of the coating showed a clear decrease with increasing distance from the substrate-coating interface. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of PO(4)(3-), and X-ray photoelectron spectroscopy (XPS) analysis on the coating top surface showed that the atomic Ca/P ratio was in the range of 1.52+/-0.15 to 1.61+/-0.07. The biological response to the coatings was also evaluated using an osteoblast precursor cell culture test. More cells and a higher integrin expression of cell attachment sites were observed on the coating surface when compared to the control group (blank titanium surface). The pull-off test showed average adhesion strengths at the coating-substrate interface to be higher than 85.12+/-5.37 MPa. Nanoindentation tests indicated that the Young's moduli of all coatings are higher than 91.747+/-3.641 GPa and microhardness values are higher than 5.275+/-0.315 GPa. While the adhesion strength results helped us to identify the best setup for substrate temperature and processing parameters to begin the deposition, the culture test and XPS results helped identifying the optimum parameters for the last stage of deposition. TEM, X-ray diffraction, FTIR and nanoidentation results were used to further evaluate the quality of the coating and optimization of its processing parameters.}, number={9}, journal={ACTA BIOMATERIALIA}, author={Bai, Xiao and Sandukas, Stefan and Appleford, Mark R. and Ong, Joo L. and Rabiei, Afsaneh}, year={2009}, month={Nov}, pages={3563–3572} }
 @article{vendra_neville_rabiei_2009, title={Fatigue in aluminum-steel and steel-steel composite foams}, volume={517}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2009.03.075}, abstractNote={The compression–compression fatigue behavior of two classes of composite metal foams (CMF) manufactured using different processing techniques, was investigated experimentally. Aluminum–steel composite foam processed using gravity casting technique comprises of steel hollow spheres and a solid aluminum alloy matrix. Steel–steel composite foam, processed using powder metallurgy (PM) technique consists of steel hollow spheres packed in a steel matrix. Under compression fatigue loading, the composite foam samples showed a high cyclic stability at maximum stress levels as high as 90 MPa. The deformation of the composite foam samples was divided into three stages – linear increase in strain with fatigue cycles (stage I), minimal strain accumulation in large number of cycles (stage II) and rapid strain accumulation within few cycles culminating in complete failure (stage III). Composite foams under cyclic loading undergo a uniform distribution of deformation, unlike the regular metal foams, which deform by forming collapse bands at weaker sections. As a result, the features controlling the fatigue life of the composite metal foams have been considered as sphere wall thickness and diameter, sphere and matrix materials, processing techniques and the bonding strength between the spheres and matrix.}, number={1-2}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Vendra, Lakshmi and Neville, Brian and Rabiei, Afsaneh}, year={2009}, month={Aug}, pages={146–153} }
 @article{neville_rabiei_2008, title={Composite metal foams processed through powder metallurgy}, volume={29}, ISSN={["0261-3069"]}, DOI={10.1016/j.matdes.2007.01.026}, abstractNote={A new closed cell composite metal foam has been produced using a powder metallurgy technique. The composite foams are processed by filling the vacancies between densely packed steel hollow spheres with steel powder and sintering them into a solid cellular structure. Three sets of samples have been processed, two of carbon steel and one of stainless steel. The relative densities of the products were in the range of 32.4–38.9%. Although denser than other foams, the materials developed in this study display superior compressive strengths and energy absorption capabilities, which caused superior strength to density ratios in our samples compared to other foams made from similar materials. The plateau strength to density ratio for the carbon steel samples were in the range of 12–31.9 MPa/(g/cm3) and for stainless steel samples 43.7 MPa/(g/cm3). The energy absorption at densification for carbon steel samples ranged from 18.9 to 41.7 MJ/m3 and for the stainless steel sample 67.8 MJ/m3.}, number={2}, journal={MATERIALS & DESIGN}, author={Neville, B. P. and Rabiei, A.}, year={2008}, pages={388–396} }
 @article{blalock_bai_narayan_rabiei_2008, title={Effect of substrate temperature on mechanical properties of calcium phosphate coatings}, volume={85B}, ISSN={["1552-4981"]}, DOI={10.1002/jbm.b.30917}, abstractNote={Abstract}, number={1}, journal={JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS}, author={Blalock, Travis L. and Bai, Xiao and Narayan, Roger and Rabiei, Afsaneh}, year={2008}, month={Apr}, pages={60–67} }
 @article{rabiei_vendra_kishi_2008, title={Fracture behavior of particle reinforced metal matrix composites}, volume={39}, ISSN={["1359-835X"]}, DOI={10.1016/j.compositesa.2007.10.018}, abstractNote={Aluminum matrix composites with various particle reinforcements have been experimentally tested to evaluate their fracture toughness. The experimental results have been compared with the fracture toughness estimates using the Hahn–Rosenfield model. It is observed that the Hahn–Rosenfield model has a validity range for reinforcement particle sizes of 5–10 μm. A modification to this model has been developed for estimating the fracture toughness of the metal matrix composites with larger particle reinforcements. The validity of the modified model has been experimentally tested. There has been a close agreement between the experimental results and the predicted toughness using the modified fracture model.}, number={2}, journal={COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING}, author={Rabiei, A. and Vendra, L. and Kishi, T.}, year={2008}, pages={294–300} }
 @article{rabiei_thomas_neville_lee_cuomo_2007, title={A novel technique for processing functionally graded HA coatings}, volume={27}, ISSN={["0928-4931"]}, DOI={10.1016/j.msec.2006.05.037}, abstractNote={Hydroxyapatite (HA) films were deposited using dual ion beam sputtering. Deposition was carried out with an in situ heat treatment at three temperature settings during deposition. X-ray diffraction of the films at the surface revealed that the deposited film is composed of hydroxyapatite crystalline and amorphous phases. Cross-sectional transmission electron microscopy analysis displayed that the films have a graded crystal structure with the crystalline layer near the substrate and the amorphous layer at the top surface. Compositional analysis was performed using SEM-EDX at the top surface as well as STEM-EDX at the cross-section of the film. The average calcium to phosphorous ratio at the surface is 1.46, obtained by SEM-EDX. The Ca/P ratios in the crystalline and amorphous layers of the film are 1.6 to 1.7, close to the ratio of 1.67 for HA.}, number={3}, journal={MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS}, author={Rabiei, A. and Thomas, B. and Neville, B. and Lee, J. W. and Cuomo, J.}, year={2007}, month={Apr}, pages={523–528} }
 @article{vendra_rabiei_2007, title={A study on aluminum-steel composite metal foam processed by casting}, volume={465}, ISSN={["1873-4936"]}, DOI={10.1016/j.msea.2007.04.037}, abstractNote={Composite metal foam (CMF), a new material belonging to the class of advanced cellular and porous materials, has been processed using gravity casting technique for the first time at North Carolina State University. This material comprises of steel hollow spheres and a solid aluminum alloy matrix. The energy absorption behavior of the material under static compression has been studied extensively. Experimental results show that CMF not only has a higher energy absorption capability than that of other commercially available metal foams produced from similar materials, but also possess a higher strength to density ratio. The microstructural analysis of the material was used to study and explain the formation of different phases at the aluminum–steel interface and their effect on the deformation behavior of the foam under compression. As the result of high strength and strain rates, the increase in energy absorption of the composite metal foam samples observed ranges over 30 times compared to that of 100% Al foams and over twice compared to that of 100% steel foams.}, number={1-2}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Vendra, Lakshmi J. and Rabiei, Afsaneh}, year={2007}, month={Sep}, pages={59–67} }
 @article{blalock_bai_rabiei_2007, title={A study on microstructure and properties of calcium phosphate coatings processed using ion beam assisted deposition on heated substrates}, volume={201}, ISSN={["0257-8972"]}, DOI={10.1016/j.surfcoat.2006.10.039}, abstractNote={In this study a set of thin Hydroxyapatite (HA) [Ca10(PO4)6(OH)2] coatings was deposited on heated silicon and titanium substrates using Ion Beam Assisted Deposition (IBAD). The effects of substrate temperature and processing parameters on the microstructural properties and composition of the coatings are being studied. Analytical techniques include transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) with an energy dispersive X-ray spectroscopy (EDS), as well as scanning electron microscopy (SEM) with EDX, X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). The current results indicate that as substrate temperature increases the Ca/P ratio of the coatings both on titanium and silicon substrates increases. The crystallinity of the coatings and the number of calcium phosphate compounds within the coating including HA also increases. STEM–EDS revealed an atomically diffused intermediate layer at the interface between the coating and substrate. XRD results along with TEM selected area diffraction (SAD) revealed that the coatings are composed of HA, other calcium phosphate, and calcium oxide compounds.}, number={12}, journal={SURFACE & COATINGS TECHNOLOGY}, author={Blalock, Travis and Bai, Xiao and Rabiei, Afsaneh}, year={2007}, month={Mar}, pages={5850–5858} }
 @article{azzi_roberts_rabiei_2007, title={A study on pressure drop and heat transfer in open cell metal foams for jet engine applications}, volume={28}, ISSN={["0261-3069"]}, DOI={10.1016/j.matdes.2005.08.002}, abstractNote={This research investigated the feasibility of placing a ring of open cell metal foam between the combustor and the turbine section of a turbojet engine to homogenize the temperatures leaving the combustor to raise the overall efficiency of such engines. Heat transfer testing on Al foam samples was done using infrared imaging to test the foam's efficiency of mixing the hot and cool temperatures with very promising results (21% and 37% mixing factor in a 10 cm thick layer of 5 and 10 PPI foam, respectively). Pressure drop testing on Al foam was also done in the compressible region of air to investigate the loss of pressure through the foam. The tests concluded that when temperature effects where accounted for, the pressure drop was less than 34.5 KPa per 2.54 cm of foam.}, number={2}, journal={MATERIALS & DESIGN}, author={Azzi, W. and Roberts, W. L. and Rabiei, A.}, year={2007}, pages={569–574} }
 @article{ramachandran_narayan_prater_2007, title={Magnetic properties of Ni-doped MgO diluted magnetic insulators Author(s}, volume={90}, ISSN={["1077-3118"]}, DOI={10.1063/1.2717574}, abstractNote={Magnesium oxide doped with Ni has been studied in two different forms: one in which the Ni ions are incorporated into the substitutional sites and the other in which Ni is present both in substitutional sites and in the form of metallic Ni precipitates embedded in the MgO matrix. Magnetic properties of these materials have been studied and correlated with the microstructural properties. There is a significant difference in the magnetic properties between the two forms. From these studies the authors envisage that a diluted magnetic insulator will be paramagnetic in the absence of intrinsic defects such as vacancies and interstitials. MgO is a good system to perform the present studies as it can be synthesized as a high quality crystal devoid of defects to a high degree. Moreover, the magnetic properties of the Ni precipitates can be used to compare the results when a diluted magnetic semiconductor material is not fully devoid of nanoclusters/precipitates and secondary phases.}, number={13}, journal={Applied Physics Letters}, author={Ramachandran, S. and Narayan, J. and Prater, J.T.}, year={2007}, month={Mar}, pages={132511} }
 @article{rabiei_blalock_thomas_cuomo_yang_ong_2007, title={Microstructure, mechanical properties, and biological response to functionally graded HA coatings}, volume={27}, ISSN={["0928-4931"]}, DOI={10.1016/j.msec.2006.05.036}, abstractNote={Hydroxyapatite (HA) [Ca10(PO4)6(OH)2] is the primary mineral content, representing 43% by weight, of bone. Applying a thin layer of HA, to the surface of a metal implant, can promote osseointegration and increase the mechanical stability of the implant. In this study, a biocompatible coating comprising an HA film with functionally graded crystallinity is being deposited on a heated substrate in an Ion Beam Assisted Deposition (IBAD) system. The microstructure of the film was studied using Transmission Electron Microscopy techniques. Finally, initial cell adhesion and cell differentiation on the coating was evaluated using ATCC CRL 1486 human embryonic palatal mesenchymal cell, an osteoblast precursor cell line. The results have shown superior mechanical properties and biological response to the functionally graded HA film.}, number={3}, journal={MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS}, author={Rabiei, Afsaneh and Blalock, Travis and Thomas, Brent and Cuomo, Jerry and Yang, Y. and Ong, Joo}, year={2007}, month={Apr}, pages={529–533} }
 @article{rabiei_neville_reese_vendra_2007, title={New Composite Metal Foams under Compressive Cyclic Loadings}, volume={539-543}, ISSN={1662-9752}, url={http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.1868}, DOI={10.4028/www.scientific.net/msf.539-543.1868}, abstractNote={New composite metal foams are processed using powder metallurgy (PM) and gravity casting techniques. The foam is comprised of steel hollow spheres, with the interstitial spaces occupied by a solid metal matrix (Al or steel alloys). The cyclic compression loading of the products of both techniques has shown that the composite metal foams have high cyclic stability at very high maximum stress levels up to 68 MPa. Under cyclic loading, unlike other metal foams, the composite metal foams do not experience rapid strain accumulation within collapse bands and instead, a uniform distribution of deformation happen through the entire sample until the densification strain is reached. This is a result of more uniform cell structure in composite metal foams compared to other metal foams. As a result, the features controlling the fatigue life of the composite metal foams have been considered as sphere wall thickness and diameter, sphere and matrix materials, and processing techniques as well as bonding strength between the spheres and matrix.}, journal={Materials Science Forum}, publisher={Trans Tech Publications, Ltd.}, author={Rabiei, Afsaneh and Neville, Brian and Reese, Nick and Vendra, Lakshmi}, year={2007}, month={Mar}, pages={1868–1873} }
 @article{rabiei_thomas_jin_narayan_cuomo_yang_ong_2006, title={A study on functionally graded HA coatings processed using ion beam assisted deposition with in situ heat treatment}, volume={200}, ISSN={["0257-8972"]}, DOI={10.1016/j.surfcoat.2005.09.027}, abstractNote={A new generation of calcium phosphate coatings with less than 1 μm thickness and graded crystallinity through the thickness of the film has been processed using ion beam assisted deposition (IBAD) and in situ heat treatment. Microstructural analysis of the film confirmed a gradual decrease of the grain size and crystallinity towards the surface, leading to nano-scale grains and eventually amorphous layer at the surface. The mechanical properties and adhesion bonding of the film have been evaluated using microscratch and nanoindentation tests and, in general, functionally graded HA films deposited using our IBAD system together with in situ heat treatment demonstrated higher modulus and hardness values than sputter-deposited films with the same thickness as well as those appearing in the literature for sintered HA. Scratch test results of both sets of samples revealed that crack formation is more common in sputter-deposited HA film than in the functionally graded HA film deposited using IBAD and in situ heat treatment. We anticipate that the functionally graded hydroxyapatite films will provide improved tissue–implant interfaces for orthopedic and dental implants.}, number={20-21}, journal={SURFACE & COATINGS TECHNOLOGY}, author={Rabiei, A and Thomas, B and Jin, C and Narayan, R and Cuomo, J and Yang, Y and Ong, JL}, year={2006}, month={May}, pages={6111–6116} }
 @article{lee_thomas_rabiei_2006, title={Microstructural study of titanium-palladium-nickel base thin film shape memory alloys}, volume={500}, ISSN={["0040-6090"]}, DOI={10.1016/j.tsf.2005.11.027}, abstractNote={Abstract A new generation of thin film shape memory alloys has been developed with 1.65 μm thickness for micro-actuator applications. In this work, the microstructure of thin film Titanium–Palladium–Nickel (TiPdNi) shape memory alloys deposited using ion beam assisted deposition from a Ti50Pd30Ni20 target is studied. The TiPdNi thin films were deposited with and without substrate heating during deposition. As-deposited films without substrate heating were found to be amorphous. Deposition on heated substrate produced a dense, columnar crystalline structure. Microstructures of bulk TiPdNi thin films as well as the interfacial region between the film and substrate were characterized by various techniques including transmission electron microscope, scanning transmission electron microscope, scanning electron microscope-energy dispersive X-ray spectroscopy and scanning transmission electron microscope-energy dispersive X-ray spectroscopy. A transition layer with 70 nm thickness is observed at the interface between the bulk film and silicon substrate. It is composed of three layers; two amorphous layers above the silicon substrate and a 50 nm thick twin absent layer, which was identified as B2 austenite phase by Fourier spectra analysis. In the bulk film, nano-scale grains in the range of 80–200 nm were observed. The width of twin band of the film was very narrower in the range of ∼5 nm.}, number={1-2}, journal={THIN SOLID FILMS}, author={Lee, JW and Thomas, B and Rabiei, A}, year={2006}, month={Apr}, pages={309–315} }
 @article{rabiei_vendra_reese_young_neville_2006, title={Processing and characterization of a new composite metal foam}, volume={47}, ISSN={["1347-5320"]}, DOI={10.2320/matertrans.47.2148}, abstractNote={New closed cell composite metal foam has been processed using both casting and powder metallurgy (PM) techniques. The foam is comprised of steel hollow spheres packed into a dense arrangement, with the interstitial spaces between spheres occupied with a solid metal matrix. Using the casting technique, an aluminum alloy infiltrates the interstitial spaces between steel spheres. In the PM technique, steel spheres and steel powder are sintered to form a solid, closed cell structure. The measured densities of the Al-Fe composite foam, low carbon steel foam, and stainless steel foam are 2.4, 2.6, and 2.9 g/cm 3 with relative densities of 42, 34, and 37%, respectively. The composite metal foams composite materials developed in this study displayed superior compressive strength as compared to any other foam being produced with similar materials. The compressive strength of the cast Al-Fe foam averaged 67 MPa over a region of 10 to 50% strain, while the low carbon steel PM foam averaged 76 MPa over the same strain region, and the stainless steel PM foam averaged 136 MPa over the same region. Densification began at approximately 50% for the cast foam and ranged from 50 to 55% for the PM foams. The strength to density ratio of the product of both techniques exceeded twice that of foams processed using other techniques with similar materials.}, number={9}, journal={MATERIALS TRANSACTIONS}, author={Rabiei, Afsaneh and Vendra, Lakshmi and Reese, Nick and Young, Noah and Neville, Brian P.}, year={2006}, month={Sep}, pages={2148–2153} }
 @article{baldwin_thomas_lee_rabiei_2006, title={Residual stresses in TiPdNi base thin film shape memory alloys}, volume={434}, ISSN={["0921-5093"]}, DOI={10.1016/j.msea.2006.06.123}, abstractNote={TiPdNi thin films with less than 2 μm thickness were produced using ion beam assisted deposition (IBAD) on heated and unheated substrates. Films deposited on unheated substrates were found to be amorphous, and subsequently annealed to induce crystallization. Residual stresses in the films were evaluated using the Stoney equation after deposition, and after annealing. Films deposited using IBAD on unheated substrates were found to have slight compressive stress (−22.4 MPa) while films deposited on heated substrates had a moderate tensile stress (176.2 MPa). Annealed films experienced extensive tensile stress (598.3 MPa), resulting in film failure.}, number={1-2}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Baldwin, E. and Thomas, B. and Lee, J. W. and Rabiei, A.}, year={2006}, month={Oct}, pages={124–130} }
 @article{narayan_hobbs_jin_rabiei_2006, title={The use of functionally gradient materials in medicine}, volume={58}, ISSN={1047-4838 1543-1851}, url={http://dx.doi.org/10.1007/S11837-006-0142-5}, DOI={10.1007/s11837-006-0142-5}, number={7}, journal={JOM}, publisher={Springer Science and Business Media LLC}, author={Narayan, Roger J. and Hobbs, Linn W. and Jin, Chunming and Rabiei, Afsaneh}, year={2006}, month={Jul}, pages={52–56} }
 @article{rabiei_at o'neill_2005, title={A study on processing of a composite metal foam via casting}, volume={404}, ISSN={["0921-5093"]}, DOI={10.1016/j.msea.2005.05.089}, abstractNote={The research sited in this paper involves the development of a new closed cell composite metal foam using gravity casting techniques. The foam is comprised of steel hollow spheres packed into a random dense arrangement, with the interstitial space between spheres infiltrated with a casting aluminum alloy. The measured density of the material is 2.4 g/cm3, with a relative density of 41.5%. The composite foam developed in this study displayed superior compressive strength and energy absorption capacity. The compressive strength averaged 67 MPa over a region of 10–50% strain, densification began at approximately 50% strain, and the energy absorption at 50% strain is 30 MJ/m3. Scanning electron microscopy (SEM)–energy dispersive X-ray spectroscopy (EDX) compositional analysis affirmed the presence of expected phases in the hollow spheres and aluminum matrix. This novel material has promising applications in the aerospace, automotive, and biomedical industries.}, number={1-2}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Rabiei, A and AT O'Neill}, year={2005}, month={Sep}, pages={159–164} }
 @article{baldwin_thomas_lee_rabiei_2005, title={Processing TiPdNi base thin-film shape memory alloys using ion beam assisted deposition}, volume={200}, ISSN={["0257-8972"]}, DOI={10.1016/j.surfcoat.2004.08.172}, abstractNote={A new generation of thin-film shape memory alloys (SMA) has been developed with less than 2 μm thickness for MEMS microactuator applications. In this study, thin-film TiPdNi SMA was processed using ion beam assisted deposition (IBAD) with and without in situ heat treatment. As-deposited films were found to be amorphous. Postdeposition annealing lead to bulk diffusion of palladium to the substrate interface and silicon into the bulk film, creating a porous cross section. Various forms of tensile failures were observed including decohesion and delamination as a result of postdeposition annealing. Effect of heating and cooling rates was studied as well as in situ heat treatment during deposition. Deposition using the IBAD technique with in situ heat treatment was successful in producing fully martensitic films 1.5 μm thick and with reduced grain size and film defects, compared to the other sputter deposited films and IBAD deposited followed by postdeposition heat treatment. The effects of various processing parameters, and heat treatment conditions, on film properties have been studied.}, number={7}, journal={SURFACE & COATINGS TECHNOLOGY}, author={Baldwin, E and Thomas, B and Lee, JW and Rabiei, A}, year={2005}, month={Dec}, pages={2571–2579} }
 @article{rabiei_enoki_kishi_2000, title={A study on fracture behavior of particle reinforced metal matrix composites by using acoustic emission source characterization}, volume={293}, ISSN={0921-5093}, url={http://dx.doi.org/10.1016/s0921-5093(00)01218-1}, DOI={10.1016/s0921-5093(00)01218-1}, abstractNote={Abstract A one directional acoustic emission (AE) source characterization has been used during a three point bending fracture toughness test on 6061 aluminum matrix composites with Al2O3 particle reinforcements of 5 and 10 μm sizes, in order to evaluate the dynamic process of micro-fracture in these materials. Different acoustic emission sources are characterized and, as a result, two types of AE events are distinguished. It is observed that at very low strain levels void nucleation is the main source for acoustic emission. At higher levels, the micro pop-in of primary voids and their eventual coalescence results in a different type of acoustic emission. In fine particle reinforced materials, when the amplitude of AE events in void nucleation at fine particles is not high enough to be detected, the main source of AE events is only the void coalescence. By increasing the particle size, the number of detectable events during void nucleation is increased.}, number={1-2}, journal={Materials Science and Engineering: A}, publisher={Elsevier BV}, author={Rabiei, A. and Enoki, M. and Kishi, T.}, year={2000}, month={Nov}, pages={81–87} }
 @article{rabiei_2000, title={Failure mechanisms associated with the thermally grown oxide in plasma-sprayed thermal barrier coatings}, volume={48}, ISSN={1359-6454}, url={http://dx.doi.org/10.1016/s1359-6454(00)00171-3}, DOI={10.1016/s1359-6454(00)00171-3}, abstractNote={The microstructure and durability of a thermal barrier coating (TBC) produced by the thermal spray method have been characterized. Upon exposure, the bond coat chemistry and microstructure change by inter-diffusion with the substrate and upon thickening of the thermally grown oxide (TGO). A wedge impression test, in conjunction with observations by scanning electron microscopy, has been used to probe the failure mechanisms. At short exposure times, when the TGO thickness is less than about 5 μm, the growth of the TGO does not affect the crack patterns in the TBC and delaminations induced by wedge impression propagate within the TBC about 30 μm from the interface. An amorphous phase at the splat interfaces promotes this failure mode. As the thickness of TGO increases during exposure, cracks form in the TBC around imperfections at the interface. Moreover, induced delaminations develop a trajectory close to the interface, propagating not only through the TBC but also within the TGO and along the interfaces. A scaling result based on the misfit around imperfections caused by TGO growth has been used to rationalize the critical TGO thickness when the TBC fails.}, number={15}, journal={Acta Materialia}, publisher={Elsevier BV}, author={Rabiei, A}, year={2000}, month={Sep}, pages={3963–3976} }
 @article{rabiei_hutchinson_evans_2000, title={Heat generation during the fatigue of a cellular Al alloy}, volume={31}, ISSN={1073-5623 1543-1940}, url={http://dx.doi.org/10.1007/s11661-000-0108-0}, DOI={10.1007/s11661-000-0108-0}, abstractNote={The heat generation from a notch during the compression-compression fatigue of a cellular Al alloy has been measured and compared with a model. The measurements indicate that heat is generated because of hysteresis occurring in narrow cyclic plastic zones outside the notch. This process continues until the notch closes. At closure, a brief period of heat generation arises because of friction along the notch faces. A plasticity model based on the Dugdale zone is shown to provide a reasonably accurate characterization of the heat generated, with the proviso that an “ineffective” zone be transposed onto the notch tip. It is found that the temperatures generated are too small to cause fatigue by thermal softening. A fatigue mechanism based on either geometric softening of the cells or crack growth in the cell walls is implied.}, number={4}, journal={Metallurgical and Materials Transactions A}, publisher={Springer Science and Business Media LLC}, author={Rabiei, A. and Hutchinson, J. W. and Evans, A. G.}, year={2000}, month={Apr}, pages={1129–1136} }
 @article{sugimura_rabiei_evans_harte_fleck_1999, title={Compression fatigue of a cellular Al alloy}, volume={269}, ISSN={0921-5093}, url={http://dx.doi.org/10.1016/s0921-5093(99)00147-1}, DOI={10.1016/s0921-5093(99)00147-1}, abstractNote={The cyclic compression of a cellular Al alloy has been evaluated. Plastic compression occurs beyond a critical number of cycles, NT. At N<NT the cumulative strains are negligible and the material has cyclic stability. At N>NT, strain accumulates rapidly and preferentially within deformation bands, until the densification strain has been reached. The bands form preferentially from large cells in the ensemble. Such cells develop plastically buckled membranes which experience large strains upon further cycling, which lead to cracks. The cracks, once formed, result in rapid cyclic straining. This feature controls the fatigue life.}, number={1-2}, journal={Materials Science and Engineering: A}, publisher={Elsevier BV}, author={Sugimura, Y and Rabiei, A and Evans, A.G and Harte, A.M and Fleck, N.A}, year={1999}, month={Aug}, pages={38–48} }
 @article{rabiei_mumm_hutchinson_schweinfest_rühle_evans_1999, title={Microstructure, deformation and cracking characteristics of thermal spray ferrous coatings}, volume={269}, ISSN={0921-5093}, url={http://dx.doi.org/10.1016/s0921-5093(99)00132-x}, DOI={10.1016/s0921-5093(99)00132-x}, abstractNote={The microstructure and local mechanical characteristics of thermal spray ferrous coatings have been determined. The emphasis has been on coatings made by the high velocity oxyfuel (HVOF) process, especially the role of Al alloy additives. The oxide phase present in the material and preferred pathways for local cracking and separation have been determined. Thin intersplat oxide layers emerge as preferential sites. These oxides are amorphous and the cracks extend along the oxide/α–Fe interfaces with low local fracture toughness, in the range 0.2–1 MPa√m. These low toughness pathways govern coating deterioration.}, number={1-2}, journal={Materials Science and Engineering: A}, publisher={Elsevier BV}, author={Rabiei, A and Mumm, D.R and Hutchinson, J.W and Schweinfest, R and Rühle, M and Evans, A.G}, year={1999}, month={Aug}, pages={152–165} }
 @article{rabiei_kim_enoki_kishi_1997, title={A new method based on simultaneous acoustic emission and in-situ sem observation to evaluate the fracture behavior of metal matrix composites}, volume={37}, ISSN={1359-6462}, url={http://dx.doi.org/10.1016/s1359-6462(97)00173-5}, DOI={10.1016/s1359-6462(97)00173-5}, abstractNote={In this study, the authors tried to combine the advantages of AE evaluation and in-situ SEM observation to analyze the fracture behavior of 6061 Al alloy matrix composites with different volume fractions and different reinforcement sizes of SiC particles. By using in situ SEM observations of crack initiation and growth together with two-channel acoustic emission (AE) linear location characterization the authors can analyze the effect of different parameters on fracture behavior of Particulate Reinforced Metal Matrix Composites (PRMMCs), and thereby lay the foundation for improving the fracture properties of this genre of composites.}, number={6}, journal={Scripta Materialia}, publisher={Elsevier BV}, author={Rabiei, A. and Kim, B.-N. and Enoki, M. and Kishi, T.}, year={1997}, month={Sep}, pages={801–808} }
 @article{rabiei_kim_enoki_kishi_1996, title={Fracture Behavior in 6061 Al Alloy Matrix Composites with Different Reinforcements}, volume={37}, ISSN={0916-1821 2432-471X}, url={http://dx.doi.org/10.2320/matertrans1989.37.1148}, DOI={10.2320/matertrans1989.37.1148}, abstractNote={The effect of reinforcement size and volume fraction on fracture toughness in powder metallurgy (P/M)- processed 6061Al alloy matrix composites with different kinds of reinforcements (Si 3 N 4 whiskers, and SiC particles) are analyzed. The acoustic emission ( AE ) activities has also been investigated during three point bending fracture toughness test. Comparing the fracture toughness results in MMCs containing different volume fractions (V f ) of whiskers and particles show higher fracture toughness in materials with lower V f . On the other hand, the fracture behavior in 10 percent reinforced composites regardless of the type of reinforcement, particle or whisker, is ductile fracture, but it is semi- brittle in the case of 30 percent reinforced materials. Regarding the amplitude and the number of AE events during three point bending fracture toughness test, 30 percent reinforced materials with brittle fracture mode show very high amplitude signals with less number of events in the onset of plastic deformation. 10 percent reinforced composites with a ductile mode fracture show lower AE amplitude and higher number of events. Totally, a kind of interaction between the different parameters like volume fraction, reinforcement type and reinforcement size on the fracture behavior of 6061 Al alloy matrix composites are observed and discussed.}, number={5}, journal={Materials Transactions, JIM}, publisher={Japan Institute of Metals}, author={Rabiei, Afsaneh and Kim, Byung-Nam and Enoki, Manabu and Kishi, Teruo}, year={1996}, pages={1148–1155} }
 @book{rabiei_1993, place={Tehran, Iran}, title={Solidification and Casting}, publisher={Jazil Publishers}, author={Rabiei, A.}, year={1993} }
 @book{rabiei_1992, place={Tehran, Iran}, edition={1st}, title={Metallography}, publisher={Jazil Publishers}, author={Rabiei, A.}, year={1992} }
 @article{rabiei_1992, title={Welding of Plastics}, number={3}, journal={DMT Scientific and Technological Journal}, author={Rabiei, Afsaneh}, year={1992} }
 @book{rabiei_1990, place={Tehran, Iran}, title={Welding of Plastics}, publisher={Shahrab Publishers}, author={Rabiei, A.}, year={1990} }
 @book{rabiei_1984, place={Tehran, Iran}, edition={1st}, title={Engineering Physical Metallurgy}, publisher={Hoseinian Publishers}, author={Rabiei, A.}, year={1984} }