Tensile Creep Behavior of HfNbTaTiZr Refractory High Entropy Alloy at Elevated Temperatures

This talk will present the tensile creep deformation of equiatomic HfNbTaTiZrr, we used the optical floating zone technique to fabricate sample with grain size larger than 1 mm on average; tensile creep tests under vacuum at 1100~1250^oC and stepwise loading of 5-30 MPa were performed. Creep of HfNbTaTiZr was dominated by solute drag creep behavior, and deformation was governed by a/2<111> type dislocations. Analysis suggests that creep rate of HfNbTaTiZr was controlled by Ta, which possesses the lowest intrinsic diffusivity in the system and contributes the most to drag dislocations. Findings in this work can provide a guideline to develop future high entropy alloys with creep resistance.