Microstructure and mechanical properties evolution in HfNbTaTiZr refractory high-entropy alloy during cold rolling

Abstract

The effect of cold rolling on the structure and mechanical properties of the HfNbTaTiZr refractory high-entropy alloy with a single body-centered cubic (BCC) phase structure is studied. The microhardness evolution during cold rolling to the thickness strain εth ¼ 80% shows three distinct stages: an increase till εth 15%, a plato in the interval 15-40%, and again some increase at εth ≥ 40%. This behavior is found to be associated with an increase in dislocation density at the first stage, the formation of kink bands at the second stage, and the development of shear bands with fine lamellar internal substructure at the third stage