Abstract Deformation mechanisms of high entropy alloys (HEAs) at cryogenic temperatures have attracted extensive research interest. We used in situ neutron diffraction to study the tensile behavior of a face-centered-cubic HEA at 77 and 15 K and compared its stacking fault energy (SFE) at ambient and cryogenic temperatures. The SFE dropped from 28 mJm−2 at 293 K to 11 mJm−2 at 15 K, leading to the transition of deformation mechanism from deformation-induced twinning to martensite phase transformation. As a result, excellent balance of strength and ductility was achieved at both temperatures. This finding highlights the importance of SFE for cryogenic alloy design.

中文翻译：

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FeCoCrNiMo0.2 高熵合金在 77 和 15 K 的变形机制

摘要 高熵合金（HEAs）在低温下的变形机制引起了广泛的研究兴趣。我们使用原位中子衍射研究了面心立方 HEA 在 77 和 15 K 下的拉伸行为，并比较了其在环境温度和低温下的堆垛层错能 (SFE)。SFE 从 293 K 时的 28 mJm-2 下降到 15 K 时的 11 mJm-2，导致变形机制从变形诱导孪晶转变为马氏体相变。结果，在两种温度下都实现了强度和延展性的出色平衡。这一发现凸显了 SFE 对低温合金设计的重要性。