Microstructure and Room Temperature Properties of a High-Entropy TaNbHfZrTi Alloy

摘要

A refractory alloy, Ta20Nb20Hf20Zr20Ti20, was produced by vacuum arc-melting. The as-solidified alloy had a dendritic structure, which was not affected by hot isostatic pressing (HIPing) conducted at T = 1200 DGC and P = 207 MPa for 3 hours. The alloy had a single-phase bodycentered cubic (BCC) structure with the lattice parameter a = 340.44 pm. The alloy density and Vickers microhardness after HIPing were p = 9.94 g/cm3 and Hv = 3826 MPa. Room temperature compression testing of HIPd samples revealed excellent ductility. The samples deformed homogeneously without any evidence of cracking at least up to 50% compression strain. Continuous strengthening followed yielding at 807 MPa. A simple model of solid-solution strengthening is proposed to explain the behavior.