The superior thermal stability and tensile properties of hot rolled W-HfC alloys

摘要

Herein, a W-0.5wt%HfC (WHC05) alloy is fabricated by conventional sintering and multi-step hot-rolling. The high-temperature stability and tensile properties at different temperatures, ranging from room temperature to 600 degrees C, are studied to demonstrate the influence of HfC addition. The results reveal that the WHC05 alloy has a higher recrystallization temperature (1400 degrees C-1500 degrees C) than the previously reported as-rolled pure W (1200 degrees C) and as-rolled W-0.5wt%ZrC (WZC05 similar to 1300 degrees C) alloy. Moreover, after recovery and recrystallization (annealing at 1600 degrees C), the WHC05 alloy maintained a high ultimate tensile strength of similar to 300 MPa and exhibited a desirable increase in total elongation (> 35%), which is similar to 1.6 times higher than the recrystallized WZC05 at 500 degrees C. The superior thermal stability and excellent high-temperature mechanical properties can be ascribed to the unique microstructure and uniform dispersion of nano-sized HfC particles in W matrix. The influence of annealing temperature on grain structure, grain orientation and distribution of nano-sized HfC particles has been studied to unveil the possible mechanism of enhanced thermal stability and superior mechanical properties.