Microstructures in a Nb-Cr-V-W-Ta high entropy alloy during annealing

Abstract

A Nb-Cr-V-W-Ta high entropy alloy has been subjected to annealing treatment at 600, 700 and 800 °C in air for 6 hours. Five different phases have been identified based on their composition in the as received condition. The annealing treatment does not alter the phase analysis and compositions except for the W-rich phase where minor changes in the composition have been observed. This is considered as an experimental evidence of sluggish diffusivity associated with HEAs. Absence of phase transformation during the heating and the minimal changes in observed compositions of the phases is an indication of the resistance to diffusion offered by the elements of the high entropy alloy. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and color X-ray elemental mapping have been used to conduct this research.