Mechanical properties of high-entropy alloys (HEAs) with the face-centered cubic (fcc) structure strongly depend on their initial grain orientations. However, the orientation-dependent mechanical responses and the underlying plastic flow mechanisms of such alloys are not yet well understood. Here, deformation of the equiatomic FeMnCoCrNi HEA with various initial orientations under uniaxial tensile testing has been studied by using atomistic simulations, showing the results consistent with the recent experiments on fcc HEAs. The quantitative analysis of the activated deformation modes shows that the initiation of stacking faults is the main plastic deformation mechanism for the crystals initially oriented with [001], [111], and [112], and the total dislocation densities in these crystals are higher than that with the [110] and [123] orientations. Stacking faults, twinning, and hcp-martensitic transformation jointly promote the plastic deformation of the [110] orientation, and twinning in this crystal is more significant than that with other orientations. Deformation in the crystal oriented with [123] is dominated by the hcp-martensite transformation. Comparison of the mechanical behaviors in the FeMnCoCrNi alloy and the conventional materials, i.e. Cu and Fe₅₀Ni₅₀, has shown that dislocation slip tends to be activated more readily in the HEA. This is attributed to the larger lattice distortion in the HEA than the low-entropy materials, leading to the lower critical stress for dislocation nucleation and elastic–plastic transition in the former. In addition, the FeMnCoCrNi HEA with the larger lattice distortion leads to an enhanced capacity of storing dislocations. However, for the [001]-oriented HEA in which dislocation slip and stacking fault are the dominant deformation mechanisms, the limited deformation modes activated are insufficient to improve the work hardening ability of the material.

具有面心立方 (fcc) 结构的高熵合金 (HEAs) 的机械性能很大程度上取决于它们的初始晶粒取向。然而，这种合金的取向相关机械响应和潜在的塑性流动机制尚不清楚。在这里，通过使用原子模拟研究了单轴拉伸试验下具有各种初始取向的等原子 FeMnCoCrNi HEA 的变形，显示结果与最近的 fcc HEA 实验一致。对活化变形模式的定量分析表明，初始以[001]、[111]和[112]取向的晶体的主要塑性变形机制是堆垛层错的发生，并且这些晶体中的总位错密度较高与 [110] 和 [123] 方向相比。堆垛层错、孪晶和hcp-马氏体相变共同促进了[110]取向的塑性变形，并且该晶体中的孪晶比其他取向的孪晶更为显着。以 [123] 取向的晶体中的变形由 hcp-马氏体转变主导。FeMnCoCrNi 合金与传统材料（即 Cu 和 Fe）的力学行为比较₅₀ Ni ₅₀表明，位错滑移在 HEA 中更容易被激活。这归因于 HEA 中的晶格畸变比低熵材料更大，导致前者的位错成核和弹塑性转变的临界应力较低。此外，具有较大晶格畸变的 FeMnCoCrNi HEA 导致存储位错的能力增强。然而，对于位错滑移和堆垛层错是主要变形机制的[001]取向HEA，激活的有限变形模式不足以提高材料的加工硬化能力。