Strain-rate sensitivity of high-entropy alloys and its significance in deformation

Abstract

Strain-rate dependence in face centered cubic high entropy alloys still remains controversial despite extensive efforts on this topic. Strain-rate sensitivity reflects underlying thermally-activated deformation and the controversy boils down to the deformation mechanism. There has been disagreement even on the experimental values of the strain-rate sensitivity and activation volume. This study reviewed and analyzed the differences in experimental values and proposed mechanisms to resolve the controversy over the nature of thermal obstacles in CrMnFeCoNi alloy. TEM study on CrMnFeCoNi supports the presence of nanoscale heterogeneity elucidating the nature of rate-controlling mechanism in the alloy. IMPACT STATEMENT: Strong temperature dependence of flow stress, high strain-rate-sensitivity and small activation-volume are key features for deformation of CrMnFeCoNi. TEM analysis supports presence of nanoscale heterogeneity acting as the rate-controlling barrier.