Effects of temperature and grain size on diffusivity of polycrystalline tungsten via molecular dynamic simulation

GQ Jiang and YX Zhang and L Hua and JB Zhao, AIP ADVANCES, 15, 085125 (2025).

DOI: 10.1063/5.0276500

The effects of grain size and temperature on the self-diffusion of polycrystalline tungsten (W) were studied using molecular dynamic simulation, focusing on the relationship between grain boundary diffusivity (D-GB), grain diffusivity (D-Grain), and effective diffusivity (D-eff). The results show that D-GB and D-Grain have a strong dependence on temperature and become larger with an increase in temperature. However, grain boundaries, which serve as the interstitial regions between grains, lack the perfect lattice structure characteristic of the grain, resulting in lower diffusion energy barriers and consequently forming rapid diffusion paths for atoms. As a result, the D-GB is larger than the D-Grain. It is worth noting that grain size has a small effect on D-GB, while D-eff increases with a decrease in grain size and an increase in temperature. In addition, the D-eff of the overall model is in good agreement with the D-eff calculated through the volume fraction weighted model equation. This indicates that their relationship can be quantitatively correlated by the structural characteristics of polycrystalline materials, reflecting the influence of different diffusion paths. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). https://doi.org/10.1063/5.0276500

Return to Publications page