Achieving a balance between mechanical properties at room and elevated temperatures of lightweight NiAlFeCrMoV high-entropy alloy

Abstract

In recent years, significant efforts have been made to develop high-performance alloys for engineering applications, including high-entropy alloys with lightweight and high ductility at room temperature and high strength at high temperature. In this work, a novel lightweight (NiAl)55(FeCrMoV)45 high-entropy alloy (HEA) was prepared using vacuum arc-melting. Its microstructure, compressive properties and deformation mechanisms were investigated. The results showed that the HEA is composed of BCC and B2 phases and has a low density of only 6.72 g/cm3. Its compressive yield strength, specific yield strength and fracture strain at room temperature are 1739.5 MPa, 258.9 MPa·cm3/g and 24.9%, respectively; and its yield strength and specific yield strength at 1073 K and 1273 K are 950.7 MPa and 141.2 MPa·cm3/g, 421.8 MPa and 62.8 MPa·cm3/g, respectively, better than that of most HEAs, refractory HEAs (RHEAs) and conventional alloys reported previously. The plastic deformation of the HEA is governed by dislocation slip at both room and elevated temperatures. The high strength of the HEA can mainly be attributed to the addition of high melting point elements Mo and V. The excellent comprehensive mechanical properties of the HEA indicate its potential application prospects in high-temperature structures.