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Characterization of Nucleation Behavior in Temperature-Induced BCC-to-HCP Phase Transformation for High Entropy Alloy
Acta Metallurgica Sinica-English Letters ( IF 3.5 ) Pub Date : 2021-07-19 , DOI: 10.1007/s40195-021-01282-6
Xiusong Huang 1 , Weibing Liao 1 , Jianjun Huang 1 , Huibin Sun 1 , Chunyan Yu 1 , Lehua Liu 2
Affiliation  

Phase transformation is one of the essential topics in the studies on high entropy alloys (HEAs). However, characterization of the nucleation behavior in the phase transformation for HEAs is still challenging through experimental methods. In the present work, HfNbTaTiZr HEA was chosen as the representative material, and molecular dynamics/Monte Carlo (MD/MC) simulations were performed to investigate the nucleation behavior in temperature-induced BCC-to-HCP transformation for this HEA system. The results indicate that Nb–Ta, Ti–Zr, Hf–Zr and Hf–Ti atom pairs are preferred in the BCC solid solution of HfNbTaTiZr HEA and Hf–Ti–Zr-rich atom cluster with chemical short range order acts as the nucleation site for HCP phase. The nucleation process follows the non-classical two-step nucleation model: BCC-like structure with severe lattice distortion forms first and then HCP structure nucleates from the BCC-like structure. Moreover, at low temperature, the BCC-to-HCP nucleation hardly occurs, and the BCC solid solution is stabilized. The present work provides more atomic details of the nucleation behavior in temperature-induced BCC-to-HCP phase transformation for HEA, and can help in deep understanding of the phase stability for HEAs.



中文翻译:

高熵合金温度诱导 BCC 到 HCP 相变中形核行为的表征

相变是高熵合金(HEAs)研究的重要课题之一。然而,通过实验方法表征 HEAs 相变中的成核行为仍然具有挑战性。在目前的工作中,HfNbTaTiZr HEA 被选为代表性材料,并进行了分子动力学/蒙特卡罗 (MD/MC) 模拟以研究该 HEA 系统在温度诱导的 BCC 到 HCP 转变中的成核行为。结果表明,Nb-Ta、Ti-Zr、Hf-Zr 和 Hf-Ti 原子对在 HfNbTaTiZr HEA 和富含 Hf-Ti-Zr 的原子团簇的 BCC 固溶体中是优选的,化学短程有序作为成核作用HCP 阶段的站点。成核过程遵循非经典的两步成核模型:具有严重晶格畸变的类 BCC 结构首先形成,然后 HCP 结构从类 BCC 结构中成核。此外,在低温下,BCC 到 HCP 的成核几乎不发生,并且 BCC 固溶体稳定。目前的工作为 HEA 的温度诱导 BCC 到 HCP 相变中的成核行为提供了更多原子细节,有助于深入了解 HEA 的相稳定性。

更新日期:2021-07-19
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