Microstructure and mechanical properties of an additively manufactured WMoTaNbNiTi refractory high-entropy alloy

WMoTaNb refractory high-entropy alloy (RHEA) is pronounced for its brilliant thermal resistance at 1600 °C, which makes it a candidate with vast potential for elevated temperature service except for its difficulty in room temperature machining before industrialization. Additive manufacturing with its complex shape forming and flexible design abilities, can intensively meet the future industrial requirements. However, the additively manufactured WMoTaNb RHEA is restricted by room-temperature brittleness before entering the market. Therefore, we newly developed a WMoTaNbNiTi RHEA, and it has been discovered that Ni, Ti, and Nb at the grain boundaries mainly formed the NiTi B19’ phase, thus sharing the residual stresses with the BCC matrix. The ductility of the as-built WMoTaNbNiTi RHEA at room temperature has thus been considerably improved. In addition, an ultimate compressive strength of 738 MPa at 1200 °C was also realized. Consequently, an ideal synergy was achieved between the as-built microstructure, and room- and high-temperature mechanical properties.