Non-equiatomic W 10 Mo 27 Cr 21 Ti 22 Al 20 high-entropy alloy produced by mechanical alloying and spark plasma sintering: Phase evolution and mechanical properties

Abstract

In this work, non-equiatomic W₁₀Mo₂₇Cr₂₁Ti₂₂Al₂₀ refractory high-entropy alloy (RHEA) was produced using mechanical alloying followed by spark plasma sintering. The phase formation, microstructure, and compressive mechanical properties of the alloy were studied. During mechanical alloying, a Body-centered cubic (BCC) solid solution phase with a particle size of less than 1 µm was obtained after 18 h ball milling. The microstructure of the sintered sample exhibits three distinct phases consisting of two solid solution phases BCC1 and BCC2 as well as fine TiC_xO_y precipitates distributed in them. The volume fractions of each phase were about 79%, 8%, and 13%, respectively. The sintered W₁₀Mo₂₇Cr₂₁Ti₂₂Al₂₀ showed yield strengths of 2465, 1506, 405, and 290 MPa at room temperature 600, 1000, and 1200°C, respectively, which are about twice that of the same refractory high-entropy alloy produced by vacuum arc melting. At 1000 and 1200°C, the strength after yielding gradually increased to 970 and 718 MPa at a compressive strain of 60%. The studied refractory high-entropy alloy can have good potential in high-temperature applications due to its high specific strength at elevated temperatures compared to conventional Ni-based superalloys and most as-reported refractory high-entropy alloys.