Microstructures and mechanical properties of TiZrHfNbTaWx refractory high entropy alloys

Refractory high-entropy alloys (RHEAs), which exhibit excellent mechanical properties at room temperature and high temperature, have received widespread attention. The TiZrHfNbTa alloy is one of the few refractory high-entropy alloys with tensile ductility. Alloying means is a common method to optimize the special properties of alloys. Here, a series of TiZrHfNbTaWx (x = 0-1) RHEAs were synthesized by arc melting technique. It showed that the fracture plasticity of the RHEAs changed from >50% of the TiZrHfNbTa to 20.7% of the TiZrHfNbTaW, and the yield strength increased from 1064 MPa of the TiZrHfNbTa to 1726 MPa of the TiZrHfNbTaW. In addition, The TiZrHfNbTaWx RHEAs predominantly consisted of a single random solid solution phase with body-centered cubic (BCC) crystal structure. The present result indicated that W addition could effectively enhance the strength of the TiZrHfNbTa alloy, while maintaining high plasticity. Finally, a simple solid solution strengthening theoretical model was proposed to explain the high yield strength, and the experimental values were in good agreement with the theoretical values. (c) 2022 Published by Elsevier B.V.