@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{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} } @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{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{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} } @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{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_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} }