Mechanical behavior and thermal activation analysis of HfNbTaTiZr body-centered cubic high-entropy alloy during tensile deformation at 77 K

Abstract

Plastic deformation of HfNbTaTiZr body-centered cubic high-entropy alloy (BCC - HEA) was investigated at 77 K. Tensile stress-strain curves showed strong temperature dependence of yield strength. Characteristics of dislocation slip at 77 K was analyzed using slip traces which confirmed active slip on {112} planes. The apparent activation volume ( V ∗) suggested thermally activated kink/kink-pair nucleation at 77 K ( V ∗~7b ³ ). V ∗values of BCC - HEA and pure Nb were nearly same at 77 K