The high thermal stability induced by a synergistic effect of ZrC nanoparticles and Re solution in W matrix in hot rolled tungsten alloy

Abstract

The synergistic effect of ZrC nanoparticle pining and Re solution in W matrix on the thermal stability of tungsten was studied by investigating the evolution of the microstructure, hardness and tensile properties after annealing in a temperature range of 1000–1700 °C. The results of metallography, electron backscatter diffraction pattern and Vickers micro-hardness indicate that the rolled W-1wt%Re-0.5 wt%ZrC alloy has a higher recrystallization temperature (1600 °C–1700 °C) than that of the rolled pure W (1200 °C), W-0.5 wt%ZrC (1300 °C), W-0.5 wt%HfC (1400–1500 °C) and W–K-3wt%Re alloy fabricated by the same technology. The molecular dynamics simulation results indicated that solution Re atoms in W matrix can slow down the self-diffusion of W atoms and form dragging effect to delay the growth of W grain, moreover, the diffusion coefficient decrease with increasing Re content. In addition, the ZrC nanoparticles can pin the grain boundaries and dislocations effectively, preventing the recrystallization. Therefore, synergistic effect of solid solution Re element and dispersed ZrC nanoparticles significantly increase recrystallization temperature.