High-entropy alloys (HEAs) with a ductile face-centered-cubic matrix and coherent nano-precipitates (L1₂) are promising candidate materials for heat-resistant applications. In the present work, we systematically investigated the mechanical behavior of a wrought L1₂-type-strengthened HEA, Al_0.5Cr_0.9FeNi_2.5V_0.2, at elevated temperatures ranging from 500 to 900 °C. We find that the Al_0.5Cr_0.9FeNi_2.5V_0.2 HEA shows a moderate strength (∼875 MPa) as well as ductility (∼15%) at 500 °C and then a distinct ductile-to-brittle transition at 600 °C due to the brittle body-centered-cubic phase and weak deformation accommodation at grain boundaries (GBs). The further increase in temperatures up to 850 °C caused a decrease in strength but an increase in ductility owing to the occurrence of dynamic restoration. Correspondingly, kernel average misorientation maps of specimens exhibited a strain concentration along GBs and different deformation accommodation abilities under various conditions.

中文翻译：

---

Al0.5Cr0.9FeNi2.5V0.2高熵合金的温度相关力学行为

具有延展性面心立方基体和相干纳米沉淀物 (L1 ₂ ) 的高熵合金 (HEA)是用于耐热应用的有前途的候选材料。在目前的工作中，我们系统地研究了锻造 L1 ₂型强化 HEA，Al _0.5 Cr _0.9 FeNi _2.5 V _0.2在 500 至 900 °C 的高温下的机械性能。我们发现 Al _0.5 Cr _0.9 FeNi _2.5 V _0.2HEA 在 500 °C 时显示出中等强度（~875 MPa）和延展性（~15%），然后在 600 °C 时由于脆性体心立方相和弱变形而出现明显的韧性到脆性转变在晶界 (GBs) 处调节。温度进一步升高至 850 °C 会导致强度下降，但由于发生动态恢复，延展性增加。相应地，样品的核平均取向差图在各种条件下表现出沿 GB 的应变集中和不同的变形适应能力。