Strain rate sensitivity (SRS) of a face-centered cubic (fcc) CoCrFeNi high-entropy alloy (HEA) with grain sizes ranging from 57 μm to 45 nm was investigated using nanoindentation, and was compared with those reported for conventional fcc metals. Experimental results show pronounced grain boundary strengthening in the HEA. Estimated values of the SRS parameter, m and activation volume, V*, indicate similar plastic deformation mechanisms in HEA and Ni in nanocrystalline regime that are grain boundary mediated. In coarse-grained regime, the high lattice friction stress in the HEA results in much higher m and smaller V* as compared to coarse grained Ni.

使用纳米压痕技术研究了晶粒中心范围为57μm至45 nm的面心立方（fcc）CoCrFeNi高熵合金（HEA）的应变率敏感性（SRS），并将其与传统的fcc金属的应变率敏感性进行了比较。实验结果表明，HEA中的晶界明显增强。SRS参数m和活化体积V *的估计值表明HEA和Ni在晶界介导的纳米晶态中具有相似的塑性变形机制。在粗粒状态下，与粗粒Ni相比，HEA中的高晶格摩擦应力导致m高得多，而V *较小。