@article{kotan_darling_saber_scattergood_koch_2013, title={An in situ experimental study of grain growth in a nanocrystalline Fe91Ni8Zr1 alloy}, volume={48}, ISSN={["0022-2461"]}, DOI={10.1007/s10853-012-7002-1}, abstractNote={Grain growth and microstructural evolution of thermally stabilized Fe91Ni8Zr1 were investigated by in situ and ex situ studies. Our investigations suggest that the microstructural evolution is fairly slow and the microstructure shows stabilization up to about 700 °C. Above this temperature, a certain fraction of grains grow abnormally into the nanocrystalline matrix, resulting in a bimodal microstructure and causing the complete loss of thermal stability. The reason for abnormal grain growth and the loss of thermal stability is identified as the appearance of the fcc γ-phase and consequent reduction in the total area of grain boundaries and the overall stored energy.}, number={5}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Kotan, Hasan and Darling, Kris A. and Saber, Mostafa and Scattergood, Ronald O. and Koch, Carl C.}, year={2013}, month={Mar}, pages={2251–2257} }
 @article{koch_scattergood_saber_kotan_2013, title={High temperature stabilization of nanocrystalline grain size: Thermodynamic versus kinetic strategies}, volume={28}, ISSN={["0884-2914"]}, DOI={10.1557/jmr.2012.429}, abstractNote={Abstract}, number={13}, journal={JOURNAL OF MATERIALS RESEARCH}, author={Koch, Carl C. and Scattergood, Ronald O. and Saber, Mostafa and Kotan, Hasan}, year={2013}, month={Jul}, pages={1785–1791} }
 @article{kotan_darling_saber_scattergood_koch_2013, title={Thermal stability and mechanical properties of nanocrystalline Fe-Ni-Zr alloys prepared by mechanical alloying}, volume={48}, ISSN={["0022-2461"]}, DOI={10.1007/s10853-013-7652-7}, number={24}, journal={JOURNAL OF MATERIALS SCIENCE}, author={Kotan, Hasan and Darling, Kris A. and Saber, Mostafa and Scattergood, Ronald O. and Koch, Carl C.}, year={2013}, month={Dec}, pages={8402–8411} }
 @article{saber_kotan_koch_scattergood_2013, title={Thermodynamic stabilization of nanocrystalline binary alloys}, volume={113}, ISSN={["0021-8979"]}, DOI={10.1063/1.4791704}, abstractNote={The work presented here was motivated by the need to develop a predictive model for thermodynamic stabilization of binary alloys that is applicable to strongly segregating size-misfit solutes, and that can use available input data for a wide range of solvent-solute combinations. This will serve as a benchmark for selecting solutes and assessing the possible contribution of thermodynamic stabilization for development of high-temperature nanocrystalline alloys. Following a regular solution model that distinguishes the grain boundary and grain interior volume fractions by a transitional interface in a closed system, we include both the chemical and elastic strain energy contributions to the mixing enthalpy ΔHmix using an appropriately scaled linear superposition. The total Gibbs mixing free energy ΔGmix is minimized with respect to simultaneous variations in the grain-boundary volume fraction and the solute contents in the grain boundary and grain interior. The Lagrange multiplier method was used to obtain numerical solutions with the constraint of fixed total solute content. The model predictions are presented using a parametric variation of the required input parameters. Applications are then given for the dependence of the nanocrystalline grain size on temperature and total solute content for selected binary systems where experimental results suggest that thermodynamic stabilization could be effective.}, number={6}, journal={JOURNAL OF APPLIED PHYSICS}, author={Saber, Mostafa and Kotan, Hasan and Koch, Carl C. and Scattergood, Ronald O.}, year={2013}, month={Feb} }
 @article{kotan_saber_koch_scattergood_2012, title={Effect of annealing on microstructure, grain growth, and hardness of nanocrystalline Fe–Ni alloys prepared by mechanical alloying}, volume={552}, ISSN={0921-5093}, url={http://dx.doi.org/10.1016/j.msea.2012.05.045}, DOI={10.1016/j.msea.2012.05.045}, abstractNote={Fe–xNi alloys from x = 0 to x = 15 with an as-milled grain size and hardness in the range of 8–11 nm and 8.5–9.5 GPa, respectively, were synthesized by ball milling. Microstructural changes, hardness, and grain growth due to annealing were characterized using X-ray diffractometry, microhardness, focused ion beam channeling contrast imaging, and optical microscopy. It was found that the composition range of single bcc phase was extended by ball milling. Subsequent annealing of MA samples resulted in reduction of hardness and extensive grain growth. It indicates that nickel has no significant effect on thermal stabilization of iron. Retained austenite was observed for Fe–8Ni and Fe–10Ni alloys annealed in the two-phase region and effect of as-milled structure on retained austenite formation was discussed.}, journal={Materials Science and Engineering: A}, publisher={Elsevier BV}, author={Kotan, H. and Saber, M. and Koch, C.C. and Scattergood, R.O.}, year={2012}, month={Aug}, pages={310–315} }
 @article{saber_kotan_koch_scattergood_2012, title={Thermal stability of nanocrystalline Fe-Cr alloys with Zr additions}, volume={556}, ISSN={["0921-5093"]}, DOI={10.1016/j.msea.2012.07.045}, abstractNote={The primary objective of this work was to determine the influence of 1–4 at% Zr additions on the thermal stability of mechanically alloyed nanocrystalline Fe–Cr alloys containing 10 and 18 at% Cr. Grain sizes based on XRD, along with microhardness changes, are reported for isochronal annealing treatments up to 1000 °C. Microstructure investigations were done using optical microscopy, channeling contrast FIB imaging, and TEM. Grain size stabilization in the nanaoscale range was maintained up to 900 °C by adding 2 at% Zr. Kinetic pinning by nanoscale intermetallic particles was identified as one source of high temperature grain size stabilization. Intermetallic particles also contribute to strengthening in addition to the Hall–Petch effect. The analysis of microhardness, XRD data, and measured values from the TEM image for Fe-10 at% Cr with 2 at% Zr suggested that both thermodynamic and kinetic mechanisms would contribute to grain size stabilization. There was no significant difference in the results for the 10 and 18 at% Cr alloys, which indicates that the α→γ transformation does not influence the grain size stabilization.}, journal={MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING}, author={Saber, Mostafa and Kotan, Hasan and Koch, Carl C. and Scattergood, Ronald O.}, year={2012}, month={Oct}, pages={664–670} }
 @inproceedings{koch_scattergood_kotan_saber, title={Thermal stability of nanocrystalline grain size in ternary FE-base alloys}, volume={753}, booktitle={Recrystallization and grain growth v}, author={Koch, C. C. and Scattergood, R. O. and Kotan, H. and Saber, M.}, pages={341–344} }