Nanoindentation Creep Behavior of CoCrFeNiMn High-Entropy Alloy under Different High-Pressure Torsion Deformations

CoCrFeNiMn high-entropy alloy (HEA) has gained increasing attention in recent years. In this work, CoCrFeNiMn HEA was prepared by arc melting and casting method; and high-pressure torsion (HPT) technology was used to refine the grains. A series of nanoindentation experiments was used to investigate the effect of different loading rates and deformations on the nanoindentation creep behavior of the CoCrFeNiMn HEA. The results show that the grain size of the CoCrFeNiMn HEA refines to the nanoscale after HPT. However, grain refinement is not obvious with further increasing HPT rotation. The loading rate and HPT rotations have an obvious effect on the nanoindentation creep behaviors of the CoCrFeNiMn HEA. The creep behaviors of the as-cast and HPT-treated CoCrFeNiMn HEA may be controlled by dislocations and the collective effect of GB sliding and dislocations, respectively.