Microstructure and Mechanical Properties of Al0.5Nb1.5TiV2-Zr0.5 Refractory High Entropy Alloy

Abstract:

The Al_0.5Nb_1.5TiV₂Zr_0.5 high entropy alloy was prepared by vacuum arc melting, and its microstructure, density, and mechanical properties were investigated. Results show that Al_0.5Nb_1.5TiV₂Zr_0.5 alloy consists of 90.6vol% body-centered cubic phase and 9.4vol% C14-Laves secondary phase. The matrix phase of the alloy is rich in Ti and V, and the secondary phase is rich in Al and Zr. The alloy has a low density of 6284 kg/m³ and Vickers hardness of 5197.9 MPa. The yield strength of alloy is decreased with increasing the temperature: it decreases from 1082.9 MPa at room temperature to 645.0 MPa at 1073 K. The compressive strain decreases from 27.20% at room temperature to 14.94% at 873 K, which is related to the decrease in atomic interaction force when the temperature rises. At 1073 K, the compressive strain of alloy exceeds 50%, indicating the good plasticity without fracture. The results of compression tests show that the ductile-brittle transition temperature ranges from 873 K to 1073 K.

Key words:Al_0.5Nb_1.5TiV₂Zr_0.5;high entropy alloy;microstructure;hardness;compressive property