The effect of strain rate on the compressive properties of an AlCoCrFeNi high-entropy alloy (HEA) was investigated. Microstructure of the AlCoCrFeNi HEA was observed using scanning transmission microscopy (SEM) and transmission electron microscopy. The results showed formation of a homogeneous two-phase structure. Quasi-static compression was tested under initial engineering strain rates between 10^–4 and 10^–2 s⁻¹. Engineering compression stress of exceeding 2500 MPa and ductility of around 12% was achieved. Dynamic mechanical behavior at room temperature was characterized by a split-Hopkinson pressure bar under strain rates between 1350 and 4000 s⁻¹. The AlCoCrFeNi HEA exhibited high strain rate sensitivity, especially under dynamic compression. The fluctuation of yield strength and the variation of strain rate hardening with strain rate was investigated. The various parameters of a constitutive equation for deformation of the AlCoCrFeNi HEA were obtained from the experimental data. The constitutive equations can be applied to predict the strength of alloy under various stain rates.

研究了应变速率对AlCoCrFeNi高熵合金（HEA）压缩性能的影响。使用扫描透射显微镜（SEM）和透射电子显微镜观察AlCoCrFeNi HEA的微观结构。结果表明形成均匀的两相结构。在初始工程应变率10 ^–4到10 ^–2  s ^-1之间测试了准静态压缩。实现了超过2500 MPa的工程压缩应力和约12％的延展性。室温下的动态力学行为的特征是在1350至4000 s ^-1的应变速率下的分裂霍普金森压力棒。AlCoCrFeNi HEA表现出高应变速率敏感性，尤其是在动态压缩下。研究了屈服强度的波动以及应变率硬化随应变率的变化。从实验数据获得用于AlCoCrFeNi HEA变形的本构方程的各种参数。本构方程可用于预测各种污染率下合金的强度。