Molecular dynamics is used to examine the evolution of dislocations and FCC → HCP phase transformation, as well as deformation twinning for a typical polycrystalline CoCrFeMnNi high-entropy alloy. It is found the discrepancy of the stress-strain curve for tension and compression owing to the strength mechanism during deformation. The grain refinement behavior is only observed in samples of compression, which leads to the difference of flow stress compared with the tension. At the early plastic stage, FCC → HCP phase transformation is the major deformation behavior. Three paths of FCC → HCP phase transformation for inducing plasticity are analyzed, and the mechanism of spontaneous nucleation of stacking faults is the mainly approach to the transformation. For large strain, the pattern of twinning induced plasticity plays a critical role on the plastic deformation of the HEA. The results are qualitatively consistent with experiments and provide a fundamental understanding of plastic deformation in FCC polycrystalline CoCrFeMnNi HEA.

分子动力学用于检查位错的演化和FCC→HCP相变，以及典型的多晶CoCrFeMnNi高熵合金的形变孪晶。发现由于变形过程中的强度机制，拉伸和压缩的应力-应变曲线存在差异。仅在压缩样品中观察到晶粒细化行为，这导致流动应力与张力相比有所不同。在塑性初期，FCC→HCP相变是主要的变形行为。分析了FCC→HCP相变诱导塑性的三个路径，而堆叠缺陷的自发成核机制是该相变的主要途径。对于大应变，孪生诱导的可塑性模式在HEA的塑性变形中起关键作用。结果与实验在质量上是一致的，并提供了对FCC多晶CoCrFeMnNi HEA中塑性变形的基本理解。