Mechanical Properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 Refractory High-Entropy Alloys. Preprint

摘要

Two refractory high entropy alloys with concentrations near Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20, were produced by vacuum arc-melting. Despite containing many constituents both alloys had a single-phase body-centered cubic (BCC) structure that remained stable after exposure to 1400 DGC. Compression properties of the alloys were determined in the temperature range of room temperature to 1600C. Limited compressive plasticity and quasi-cleavage fracture at room temperature suggests that the ductile-to-brittle transition for these alloys occurs above room temperature. At 600DGC and above, both alloys showed extensive compressive plastic strain. The yield strength dropped by 30-40% between room temperature and 600C, but was relatively insensitive to temperature above 600C . The yield strength values of both alloys were high over the entire temperature range relative to conventional superalloys.