Activation energy for plastic flow in nanocrystalline CoCrFeMnNi high-entropy alloy: A high temperature nanoindentation study

Abstract

Nanoindentation experiments in the temperature (7) range of 298 and 573 K were performed to determine the activation energy (Q) for the plastic flow in a nanocrystalline CoCrFeMnNi high-entropy alloy, which was synthesized using high-pressure torsion. A marked increase in Q from similar to 0.5 to similar to 1.8 eV was observed when T is increased from 473 to 523 K, which correspond to similar to 0.3 and similar to 0.34 T-m (T-m: melting temperature), respectively. Detailed analysis reveals that this transition is associated with the additional activation of the grain boundary diffusion mechanism in enhancing plasticity.