Al_0.3CoCrFeNi high-entropy alloys (HEAs) have attracted the attention of researchers owing to their excellent mechanical properties. In this study, Al_0.3CoCrFeNi HEAs with typical grain microstructures were fabricated and subjected to tensile tests, along with in situ scanning electron microscopy–electron backscatter deformation (SEM–EBSD), to determine the relationship between the grain microstructure, plastic deformation, and mechanical properties. The in situ EBSD analysis showed that the HEA sample with fine grains (FGs) exhibited more significant grain boundary deformation than that with coarse grains (CGs). The FG sample had a more uniform dislocation density distribution than the CG sample, and no noticeable excessive dislocation density was observed inside the grain. This indicates that the plastic deformation of the FG sample could be distributed more homogeneously without a prominent local stress concentration. Based on the grain structures from EBSD scans, crystal plasticity finite element modeling (CPFEM) and analysis were conducted to analyze the grain-level stress and strain heterogeneities. The results showed that during the tensile process, high stress was initially distributed near the B2 phase and subsequently at the grain boundaries of the HEA with increase in tensile deformation. The local stress distribution in the matrix was significantly affected by the B2 phase. Although high stress was distributed near the B2 phase during plastic deformation, the probability of crack initiation at the phase boundaries was low. This can be partly attributed to the formation of deformation twins at the junction of the B2 phase and FCC matrix, which releases the stress.

Al _0.3 CoCrFeNi高熵合金（HEAs）由于其优异的力学性能引起了研究人员的关注。在本研究中，Al _0.3制造具有典型晶粒微观结构的 CoCrFeNi HEA 并进行拉伸测试，以及原位扫描电子显微镜-电子背散射变形 (SEM-EBSD)，以确定晶粒微观结构、塑性变形和机械性能之间的关系。原位 EBSD 分析表明，细晶粒 (FG) 的 HEA 样品比粗晶粒 (CG) 表现出更显着的晶界变形。FG样品比CG样品具有更均匀的位错密度分布，并且在晶粒内部没有观察到明显的过度位错密度。这表明FG样品的塑性变形可以更均匀地分布而没有明显的局部应力集中。基于 EBSD 扫描的晶粒结构，进行晶体塑性有限元建模（CPFEM）和分析，以分析晶粒级应力和应变的异质性。结果表明，在拉伸过程中，随着拉伸变形的增加，高应力最初分布在 B2 相附近，随后分布在 HEA 的晶界处。基体中的局部应力分布受到 B2 相的显着影响。虽然在塑性变形过程中高应力分布在 B2 相附近，但在相界处产生裂纹的概率很低。这可以部分归因于在 B2 相和 FCC 基体的交界处形成变形孪晶，从而释放了应力。结果表明，在拉伸过程中，随着拉伸变形的增加，高应力最初分布在 B2 相附近，随后分布在 HEA 的晶界处。基体中的局部应力分布受到 B2 相的显着影响。虽然在塑性变形过程中高应力分布在 B2 相附近，但在相界处产生裂纹的概率很低。这可以部分归因于在 B2 相和 FCC 基体的交界处形成变形孪晶，从而释放了应力。结果表明，在拉伸过程中，随着拉伸变形的增加，高应力最初分布在 B2 相附近，随后分布在 HEA 的晶界处。基体中的局部应力分布受到 B2 相的显着影响。虽然在塑性变形过程中高应力分布在 B2 相附近，但在相界处产生裂纹的概率很低。这可以部分归因于在 B2 相和 FCC 基体的交界处形成变形孪晶，从而释放了应力。虽然在塑性变形过程中高应力分布在 B2 相附近，但在相界处产生裂纹的概率很低。这可以部分归因于在 B2 相和 FCC 基体的交界处形成变形孪晶，从而释放了应力。虽然在塑性变形过程中高应力分布在 B2 相附近，但在相界处产生裂纹的概率很低。这可以部分归因于在 B2 相和 FCC 基体的交界处形成变形孪晶，从而释放了应力。