@article{oni_broderick_rajan_lebeau_2016, title={Atom site preference and gamma '/gamma mismatch strain in Ni-Al-Co-Ti superalloys}, volume={73}, ISSN={["1879-0216"]}, DOI={10.1016/j.intermet.2016.03.006}, abstractNote={The structure and chemistry of NiCoAlTi quaternary superalloys are investigated at the microstructural and atomic scale. Atom probe tomograghy (APT) is used to quantify phase compositions and elemental partitioning behavior. Using aberration corrected electron microscopy, the site occupancy of the atoms within the A3 B structure (L12–type) γ′ phase is determined via atomic resolution energy dispersive X-ray spectroscopy (EDX). Ni is observed to preferentially occupy the A sub-lattice positions for all alloys, while Al and Ti occupy the B sub-lattice. In contrast, Co's site preference changes from a random distribution to the A sub-lattice as the alloy composition changes, in agreement with theoretical predictions from literature. Finally, the lattice strain across the γ′/γ interfaces is measured as a function of alloy composition.}, journal={INTERMETALLICS}, author={Oni, A. A. and Broderick, S. R. and Rajan, K. and LeBeau, J. M.}, year={2016}, month={Jun}, pages={72–78} }
 @article{zaddach_niu_oni_fan_lebeau_irving_koch_2016, title={Structure and magnetic properties of a multi-principal element Ni-Fe-Cr-Co-Zn-Mn alloy}, volume={68}, ISSN={["1879-0216"]}, DOI={10.1016/j.intermet.2015.09.009}, abstractNote={A nanocrystalline alloy with a nominal composition of Ni20Fe20Cr20Co20Zn15Mn5 was produced by mechanical alloying and processed using annealing treatments between 450 and 600 °C for lengths from 0.5 to 4 h. Analysis was conducted using x-ray diffraction, transmission electron microscopy, magnetometry, and first-principles calculations. Despite designing the alloy using empirical high-entropy alloy guidelines, it was found to precipitate numerous phases after annealing. These precipitates included a magnetic phase, α-FeCo, which, after the optimal heat treatment conditions of 1 h at 500 °C, resulted in an alloy with reasonably good hard magnetic properties. The effect of annealing temperature and time on the microstructure and magnetic properties are discussed, as well as the likely mechanisms that cause the microstructure development.}, journal={INTERMETALLICS}, author={Zaddach, A. J. and Niu, C. and Oni, A. A. and Fan, M. and LeBeau, J. M. and Irving, D. L. and Koch, C. C.}, year={2016}, month={Jan}, pages={107–112} }
 @article{dycus_harris_sang_fancher_findlay_oni_chan_koch_jones_allen_et al._2015, title={Accurate Nanoscale Crystallography in Real-Space Using Scanning Transmission Electron Microscopy}, volume={21}, ISSN={["1435-8115"]}, DOI={10.1017/s1431927615013732}, abstractNote={Abstract}, number={4}, journal={MICROSCOPY AND MICROANALYSIS}, author={Dycus, J. Houston and Harris, Joshua S. and Sang, Xiahan and Fancher, Chris M. and Findlay, Scott D. and Oni, Adedapo A. and Chan, Tsung-ta E. and Koch, Carl C. and Jones, Jacob L. and Allen, Leslie J. and et al.}, year={2015}, month={Aug}, pages={946–952} }
 @article{jones_lebeau_nikkel_oni_dycus_cozzan_lin_chernatynskiy_nino_sinnott_et al._2015, title={Combined experimental and computational methods reveal the evolution of buried interfaces during synthesis of ferroelectric thin films}, volume={2}, number={10}, journal={Advanced Materials Interfaces}, author={Jones, J. L. and LeBeau, J. M. and Nikkel, J. and Oni, A. A. and Dycus, J. H. and Cozzan, C. and Lin, F. Y. and Chernatynskiy, A. and Nino, J. C. and Sinnott, S. B. and et al.}, year={2015} }
 @article{raju_oni_godwal_yan_drozd_srinivasan_lebeau_rajan_saxena_2015, title={Effect of B and Cr on elastic strength and crystal structure of Ni3Al alloys under high pressure}, volume={619}, ISSN={["1873-4669"]}, DOI={10.1016/j.jallcom.2014.09.012}, abstractNote={Samples of Ni3Al, Ni3Al:B and Ni–Al–Cr super alloys were prepared by directional solidification method and their effect of alloying with ternary elements on the mechanical properties was investigated. In-situ X-ray diffraction studies were carried out on undoped Ni3Al, Ni3Al:B with boron 500 ppm and Ni–Al–Cr with 7.5 at.% of chromium super alloys at high pressure using diamond anvil cell. The results indicate that micro-alloying with B forms γ′-phase (L12 structure), similar to the pure Ni 3Al, while Ni–Al–Cr alloy consists of γ′ precipitates in a matrix of γ-phase (Ni-FCC structure). The crystal structure of all three alloys was stable up to 20 GPa. Micro alloying with boron increases bulk modulus of Ni3Al by 8% whereas alloying with chromium has the opposite effect decreasing the modulus by 11% when compared to undoped alloy. Further, the elastic modulus and hardness of Ni3Al, Ni3Al:B and Ni–Al–Cr alloys were determined using the nano-indentation technique, in combination with compressibility data which enabled the estimation of shear modulus and Poisson’s ratio of these alloys.}, journal={JOURNAL OF ALLOYS AND COMPOUNDS}, author={Raju, S. V. and Oni, A. A. and Godwal, B. K. and Yan, J. and Drozd, V. and Srinivasan, S. and LeBeau, J. M. and Rajan, K. and Saxena, S. K.}, year={2015}, month={Jan}, pages={616–620} }
 @article{oni_sang_raju_dumpala_broderick_kumar_sinnott_saxena_rajan_lebeau_2015, title={Large area strain analysis using scanning transmission electron microscopy across multiple images}, volume={106}, ISSN={["1077-3118"]}, DOI={10.1063/1.4905368}, abstractNote={Here, we apply revolving scanning transmission electron microscopy to measure lattice strain across a sample using a single reference area. To do so, we remove image distortion introduced by sample drift, which usually restricts strain analysis to a single image. Overcoming this challenge, we show that it is possible to use strain reference areas elsewhere in the sample, thereby enabling reliable strain mapping across large areas. As a prototypical example, we determine the strain present within the microstructure of a Ni-based superalloy directly from atom column positions as well as geometric phase analysis. While maintaining atomic resolution, we quantify strain within nanoscale regions and demonstrate that large, unit-cell level strain fluctuations are present within the intermetallic phase.}, number={1}, journal={APPLIED PHYSICS LETTERS}, author={Oni, A. A. and Sang, X. and Raju, S. V. and Dumpala, S. and Broderick, S. and Kumar, A. and Sinnott, S. and Saxena, S. and Rajan, K. and LeBeau, J. M.}, year={2015}, month={Jan} }
 @article{niu_zaddach_oni_sang_hurt_lebeau_koch_irving_2015, title={Spin-driven ordering of Cr in the equiatomic high entropy alloy NiFeCrCo}, volume={106}, ISSN={["1077-3118"]}, DOI={10.1063/1.4918996}, abstractNote={Spin-driven ordering of Cr in an equiatomic fcc NiFeCrCo high entropy alloy (HEA) was predicted by first-principles calculations. Ordering of Cr is driven by the reduction in energy realized by surrounding anti-ferromagnetic Cr with ferromagnetic Ni, Fe, and Co in an alloyed L12 structure. The fully Cr-ordered alloyed L12 phase was predicted to have a magnetic moment that is 36% of that for the magnetically frustrated random solid solution. Three samples were synthesized by milling or casting/annealing. The cast/annealed sample was found to have a low temperature magnetic moment that is 44% of the moment in the milled sample, which is consistent with theoretical predictions for ordering. Scanning transmission electron microscopy measurements were performed and the presence of ordered nano-domains in cast/annealed samples throughout the equiatomic NiFeCrCo HEA was identified.}, number={16}, journal={APPLIED PHYSICS LETTERS}, author={Niu, C. and Zaddach, A. J. and Oni, A. A. and Sang, X. and Hurt, J. W., III and LeBeau, J. M. and Koch, C. C. and Irving, D. L.}, year={2015}, month={Apr} }
 @article{sang_oni_lebeau_2014, title={Atom Column Indexing: Atomic Resolution Image Analysis Through a Matrix Representation}, volume={20}, ISSN={["1435-8115"]}, DOI={10.1017/s1431927614013506}, abstractNote={Abstract}, number={6}, journal={MICROSCOPY AND MICROANALYSIS}, author={Sang, Xiahan and Oni, Adedapo A. and LeBeau, James M.}, year={2014}, month={Dec}, pages={1764–1771} }
 @article{oni_hook_maria_lebeau_2014, title={Phase coexistence in Ti6Sn5 intermetallics}, volume={51}, ISSN={["1879-0216"]}, DOI={10.1016/j.intermet.2014.03.002}, abstractNote={Here we report the structural characterization of a complex Ti–Sn intermetallic compound, Ti6Sn5. From X-ray diffraction, the resulting compound was observed to exist in both orthorhombic and hexagonal phases. Analysis by electron microscopy revealed that “planar-like” defects form throughout the material. Atomic resolution aberration-corrected scanning transmission electron microscopy reveals that these “planar-like” defects represent the coexistence of the orthorhombic and hexagonal phases within single grains. The resulting interwoven phases range in thickness from a fraction to multiple unit cells and exhibit coherent phase boundaries with the matrix grain.}, journal={INTERMETALLICS}, author={Oni, A. A. and Hook, D. and Maria, J. P. and LeBeau, J. M.}, year={2014}, month={Aug}, pages={48–52} }
 @article{mily_oni_lebeau_liu_brown-shaklee_ihlefeld_maria_2014, title={The role of terminal oxide structure and properties in nanothermite reactions}, volume={562}, ISSN={["0040-6090"]}, DOI={10.1016/j.tsf.2014.05.005}, journal={THIN SOLID FILMS}, author={Mily, E. J. and Oni, A. and LeBeau, J. M. and Liu, Y. and Brown-Shaklee, H. J. and Ihlefeld, J. F. and Maria, J. -P.}, year={2014}, month={Jul}, pages={405–410} }
 @article{sarac_anderson_pearce_railsback_oni_white_hensley_lebeau_melechko_tracy_2013, title={Airbrushed Nickel Nanoparticles for Large-Area Growth of Vertically Aligned Carbon Nanofibers on Metal (Al, Cu, Ti) Surfaces}, volume={5}, ISSN={["1944-8244"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000330016500022&KeyUID=WOS:000330016500022}, DOI={10.1021/am401889t}, abstractNote={Vertically aligned carbon nanofibers (VACNFs) were grown by plasma-enhanced chemical vapor deposition (PECVD) using Ni nanoparticle (NP) catalysts that were deposited by airbrushing onto Si, Al, Cu, and Ti substrates. Airbrushing is a simple method for depositing catalyst NPs over large areas that is compatible with roll-to-roll processing. The distribution and morphology of VACNFs are affected by the airbrushing parameters and the composition of the metal foil. Highly concentrated Ni NPs in heptane give more uniform distributions than pentane and hexanes, resulting in more uniform coverage of VACNFs. For VACNF growth on metal foils, Si micropowder was added as a precursor for Si-enriched coatings formed in situ on the VACNFs that impart mechanical rigidity. Interactions between the catalyst NPs and the metal substrates impart control over the VACNF morphology. Growth of carbon nanostructures on Cu is particularly noteworthy because the miscibility of Ni with Cu poses challenges for VACNF growth, and carbon nanostructures anchored to Cu substrates are desired as anode materials for Li-ion batteries and for thermal interface materials.}, number={18}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Sarac, Mehmet F. and Anderson, Bryan D. and Pearce, Ryan C. and Railsback, Justin G. and Oni, Adedapo A. and White, Ryan M. and Hensley, Dale K. and LeBeau, James M. and Melechko, Anatoli V. and Tracy, Joseph B.}, year={2013}, month={Sep}, pages={8955–8960} }