Refractory High-Entropy Alloys (Preprint)

Two refractory alloys, W-Nb-Mo-Ta and W-Nb-Mo-Ta-V, with near-equiatomic compositions were produced by vacuum arc-melting. Both alloys have a single-phase body-centered cubic (BCC) structure. The lattice parameters a = 3.2134 A for the quaternary alloy and a = 3.1832 A for the quinternary alloy were determined with the use of a high-energy X-ray diffraction and the scattering vector length range from 0.7 to 20 A-1. The alloy density and Vickers microhardness were p = 13.75 g/cm3 and Hv = 4455 MPa for the W-Nb-Mo-Ta alloy and p = 12.36 g/cm3 and Hv = 5250 MPa for the W-Nb-Mo- Ta-V alloy. The higher microhardness was related to the finer grain structure in the quinternary alloy. Prepared in cooperation with Air Force Research Lab., General Dynamics, Dayton, OH and Tennessee Univ. Jnl article submitted to Jnl of Alloys and Compounds.