Phase-field simulations of the recrystallization and the mechanical property response in deformed tungsten

Abstract

Previous experimental studies have demonstrated that the recrystallization in nuclear materials is very sensitive to the annealing temperature, dislocation density, and original grain morphology. However, the synergistic effect of these intrinsic and extrinsic factors on recrystallization has been rarely studied due to the elevated temperatures of recrystallization and the costliness of experiments, especially in tungsten (W). In the present work, we have developed an approach that combines a phase-field model with the physics-based classical nucleation theory to study the synergistic impact of these factors on the recrystallization process. We systematically investigate the synergistic effect of annealing temperature, dislocation density, and original grain morphology on the recrystallization rate and the average recrystallized grain size. The simulation results show that increasing the dislocation density and the annealing temperature can effectively reduce the average grain size after full recrystallization. For an annealing temperature above 1523 K, the recrystallization rates have minor changes with increasing the dislocation density and annealing temperature. Furthermore, we employ an empirical model to quantitatively calculate the Vickers hardness of deformed W during the recrystallization process based on the phase-field microstructures. Notably, columnar grain crystals are found to be more effective in reducing irradiation hardness than isometric grain crystals. We believe that these simulations can provide a valuable reference for the preparation and design of radiation-resistant W materials.

Keywords

• Phase-field
• Recrystallization
• Hardness
• Tungsten