Microstructure and mechanical properties of a refractory HfNbTiVSi0.5 high-entropy alloy composite

Abstract

A refractory high-entropy alloy of HfNbTiVSi0.5 was synthesized by induction levitation melting. The alloy is a composite composed mainly of a body centered cubic (BCC) solid solution and a multi-component silicide ((Hf, Nb, Ti)-Si). This alloy displays a balanced combination of strength at high temperature and ductility at room temperature. The studied results show that the compressive yield strength (YS) is as high as 1399MPa, with a fracture strain of 10.9% at room temperature. At 800°C and 1000°C, the YS is still preserved at 875MPa and 240MPa, respectively, due to the higher load-carrying capacity of the silicide at elevated temperatures. Comparison to similar refractory HEAs shows that, the composite microstructure is beneficial for better room temperature strength and ductility as well as the elevated temperature properties.