ABSTRACT

The refractory high-entropy alloys (RHEAs) have been the subject of considerable research in recent years. Since the Laves phase usually leads to a dramatic decrease in the malleability of RHEAs at ambient temperatures, it is critical to identifying the Laves-phase formation. Here, a facile and effective criterion is proposed to predict the phase stability based on the empirical parameters of reported RHEAs. The results indicate that the small atomic size difference is a sufficient condition for determining the stability of solid solution but not a necessary one. In general, the Laves-phase precipitates can be inhibited by decreasing the atomic-size difference, the enthalpy of mixing, and the valence electron concentration. These criteria can be easily adapted to design new RHEAs with the desired phase structure.

摘要

难熔高熵合金（RHEAs）是近年来大量研究的主题。由于 Laves 相通常会导致 RHEA 在环境温度下的延展性急剧下降，因此识别 Laves 相的形成至关重要。在这里，提出了一种简单有效的标准来预测基于报告的 RHEA 的经验参数的相稳定性。结果表明，较小的原子尺寸差异是确定固溶体稳定性的充分条件，但不是必要条件。一般来说，可以通过降低原子尺寸差、混合焓和价电子浓度来抑制 Laves 相沉淀。这些标准可以很容易地适应设计具有所需相结构的新 RHEA。