DOE OSTI · 2571005
Compositional effect on pressure-induced polymorphism in high-entropy alloys
Abstract
Recently, pressure-induced polymorphic phase transitions were discovered in several fragmented high-entropy alloys (HEAs), offering a valuable opportunity to deepen our understanding of these materials. However, the chemical and physical factors that govern these transitions are still unclear. Here, in this work, we combined in situ high-pressure synchrotron X-ray diffraction, X-ray emission spectroscopy (XES), and high-resolution transmission electron microscopy (HRTEM) to systematically study the evolution of the atomic and electronic structures in the Cantor alloy and its face-centered-cubic ( fcc ) subset alloys (CoCrFeMnNi, CoCrFeNi, CoCrMnNi, CoFeMnNi, CoCrNi, CoFeNi, CoMnNi, CrFeNi, and FeMnNi). Surprisingly, diverse behavior was observed among these closely related alloys during compression and decompression, which includes irreversible, reversible fcc to hexagonal close-packed (hcp) phase transitions, or even no detectable phase transitions up to ∼40 GPa. HRTEM measurements confirmed that the fcc and hcp phases abided by the classic Shoji-Nishiyama orientation relationship during the transitions. XES data indicated that high-pressure suppresses the local magnetic moments in all the studied alloys, suggesting that magnetic states do not significantly influence the polymorphic transitions. By comparing the effects of the atomic size difference, entropy, valence electron concentration, and stacking fault energy across all the compositions studied, only the stacking fault energy shows a strong correlation with the phase transitions, indicating it plays a key role in inducing polymorphism in HEAs.
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Zhang, Fei [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai (China); Univ. of Science and Technology, Beijing (China); Chinese Academy of Sciences (CAS), Beijing (China)], Lou, Hongbo [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai (China); Inst. for Shanghai Advanced Research in Physical Sciences (China)] (ORCID:0000000250562576), Liu, Yuxin [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai (China)], Zeng, Zhidan [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai (China)], Chen, Xiehang [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai (China)], Prakapenka, Vitali [Univ. of Chicago, IL (United States)], Greenberg, Eran [Univ. of Chicago, IL (United States)] (ORCID:0000000216300628), Yan, Jinyuan [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Univ. of California, Santa Cruz, CA (United States)] (ORCID:0000000277708037), Xiao, Yuming [Argonne National Laboratory (ANL), Argonne, IL (United States)], Chow, Paul [Argonne National Laboratory (ANL), Argonne, IL (United States)], Kawaguchi, Saori I. [Japan Synchrotron Radiation Research Institute, Sayo, Hyogo (Japan)], Wen, Jianguo [Argonne National Laboratory (ANL), Argonne, IL (United States). Center for Nanoscale Materials (CNM)], Sheng, Huaping [Argonne National Laboratory (ANL), Argonne, IL (United States). Center for Nanoscale Materials (CNM); Wuhan Univ. (China)] (ORCID:0000000182684247), Wu, Yuan [Univ. of Science and Technology, Beijing (China)], Lu, Zhaoping [Univ. of Science and Technology, Beijing (China)], Zeng, Qiaoshi [Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai (China); Inst. for Shanghai Advanced Research in Physical Sciences (China)] (ORCID:0000000159601378). 2024-12-05. Compositional effect on pressure-induced polymorphism in high-entropy alloys. https://doi.org/10.1016/j.mtchem.2024.102435
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