ABSTRACT The influences of chemical disorder and external loading conditions on the reversible structural transformation between hexagonal close-packed (HCP) and face centred cubic (FCC) phases in CrCoFeNi high entropy alloys (HEAs) are studied from first-principles calculations. The generalised planar fault energy curves are utilised to analyse the competition between the transformation and deformation twining in the HEA. It is found that the transformation-induced plasticity (TRIP) could occur in CrCoFeNi HEA through the reversible HCP-to-FCC transformation under hydrostatic pressures or uniaxial tensions, which is enhanced in the regions with high or low local concentration of Co or Ni, respectively. These findings well explain on the TRIP in CrCoFeNi HEAs from an energetics perspective, and provide useful information on the effects of chemical disorder on dislocation activities in HEAs. The results reported in this work could facilitate the development of HEAs with structural transformation accommodated plasticity.

中文翻译：

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化学无序和外部加载条件对 CrCoFeNi 高熵合金中 HCP 和 FCC 相之间结构转变的影响：第一性原理研究

摘要 从第一性原理计算研究了化学无序和外部载荷条件对 CrCoFeNi 高熵合金 (HEAs) 中六方密堆积 (HCP) 和面心立方 (FCC) 相之间可逆结构转变的影响。利用广义平面断层能量曲线分析了HEA中转变和变形缠绕之间的竞争。发现在静水压力或单轴张力下，CrCoFeNi HEA 可通过可逆的 HCP 到 FCC 转变发生转变诱导塑性（TRIP），这种转变在 Co 或 Ni 局部浓度高或低的区域增强，分别。这些发现从能量学的角度很好地解释了 CrCoFeNi HEAs 中的 TRIP，并提供有关化学无序对 HEAs 位错活动影响的有用信息。这项工作中报告的结果可以促进具有可塑性的结构转变的 HEA 的开发。