Microstructure and elevated-temperature mechanical properties of refractory AlMo0.5NbTa0.5TiZr High Entropy Alloy fabricated by powder metallurgy

TL;DR

This study demonstrates the successful design and fabrication of a refractory high-entropy alloy using powder metallurgy, resulting in a microstructure with two BCC phases and excellent high-temperature mechanical properties.

Contribution

It introduces a powder metallurgy approach to produce a refractory high-entropy alloy with distinct BCC phases, improving microstructure control and mechanical performance.

Findings

Two BCC phases identified: disordered and ordered.

High microhardness of 678HV achieved.

Strong high-temperature strength with 964MPa at 1273K.

Abstract

New approaches for the design of alloy systems with multiprincipal elements is recently researched in refractory materials field. However, most research aimed at arc melting process with weakness of coarsening of grains and inhomogeneous microstructure of segregation of elements during the cooling. This study aims to design and fabricate high-entropy alloy with powder metallurgy. In this study, a refractory high entropy alloys with composition near AlMo0.5NbTa0.5TiZr were produced by powder metallurgy. The alloy consists of two body-centered cubic (BCC) phases. One phase was disordered BCC enriched with Mo, Nb and Ta and the other phase was ordered BCC enriched with Al and Zr. The AlMo0.5NbTa0.5TiZr alloy had a density of 7.46g/cm3 and Vickers microhardness of 678HV. Its compressive yield strength was 2466MPa at 298K and 964MPa at 1273K. The properties of the alloy and the beneficial effects from powder metallurgy on the microstructure and properties were outlined.