Effect of Ti additions on mechanical properties of NbMoTaW and VNbMoTaW refractory high entropy alloys

With Ti addition in a NbMoTaW alloy, a new refractory high entropy alloy (HEA) of TiNbMoTaW was developed. It has been found that this HEA possesses single body-centered cubic (BCC) phase structure, and could sustain the phase structure even after annealing at 1200 °C for 24 h. In comparison with the mechanical properties of the NbMoTaW and VNbMoTaW HEAs, the room-temperature yield strengths and compressive plastic strains of the TiNbMoTaW and TiVNbMoTaW HEAs are significantly enhanced. In particular, the TiNbMoTaW and TiVNbMoTaW HEAs also show very promising high temperature strength. Their yield strengths are as high as ∼586 and ∼659 MPa at 1200 °C, respectively. The present results indicate that Ti addition is beneficial to the strength and the compressive ductility of the refractory HEAs at room-temperature. It is suggested that the present refractory HEAs possess the potentials in applications of high temperature structure materials.