Compressive creep behavior of an oxide-dispersion-strengthened CoCrFeMnNi high-entropy alloy

Abstract

Creep tests of two equiatomic CoCrFeMnNi alloys were conducted in the temperature range from 973 K to 1073 K. The alloys were prepared by milling blends of powders of pure elements in a planetary ball mill and compacting by the spark plasma technique. Two variants of the alloys were prepared: (i) without and (ii) with the dispersion of oxides. Creep resistance was substantially improved by the presence of oxides. Diffusion creep controlled by lattice diffusion was suggested as a possible mechanism at low stresses. The effective diffusion coefficient calculated for Nabarro-Herring creep was comparable to the lattice diffusion coefficient of Ni in the same high-entropy alloy. At high stresses, the creep behavior was characterized by the presence of a threshold stress invoked by oxide particles.