Microstructure and room temperature properties of a high-entropy TaNbHfZrTi alloy

A new refractory alloy, Ta20Nb20Hf20Zr20Ti20, produced by vacuum arc-melting followed by hot isostatic pressing (HIPing) at T = 1473 K and P = 207 MPa for 3 h has predominantly a single-phase body-centered cubic (BCC) structure with the lattice parameter a = 340.4 pm. The alloy density and Vickers microhardness are ρ = 9.94 g/cm3 and Hv = 3826 MPa. The alloy has high compression yield strength (σ0.2 = 929 MPa) and ductility (ɛ > 50%). The alloy shows considerable strain hardening and homogeneous deformation. A simple model of solid-solution strengthening is proposed to explain the behavior.