The model treats multiple concurrent physical processes, i.e., rigid-body translation and rotation of powder particles, grain growth through boundary migration, and various diffusion mechanisms including surface diffusion, grain boundary diffusion, volume diffusion, and vapor transport through evaporation and condensation.
Our computations account for grain boundary sliding, grain boundary diffusion, grain boundary migration, and surface diffusion, as well as thermally activated dislocation creep within the grains themselves.
Thus, the chemical driving force is considered to be the most important driving force for the grain boundary migration and the boundary diffusion along the grain boundaries in the DIR region is recognized to be the rate controlling process of DIR.
A steady-state grain size is maintained in the recrystallized structure following yielding due to boundary migration and grain rotation mechanisms, rather than by diffusion-based dislocation climb.
They moreover slow down micrograin boundary migration and impede reactions between dislocations and subgrain boundaries.
A comparison of the activation energies determined shows that grain-boundary migration and self-diffusion are distinctly different processes.
A new set of finite element formulations are presented in this paper to model surface diffusion, grain-boundary diffusion, grain-boundary migration and their interaction.
In a previous paper [J. Comput. Phys. 196 (2004) 724], we presented a set of finite element formulations to model surface diffusion, grain-boundary diffusion and grain-boundary migration, and their interactions.
Bonding occurs by local grain boundary migration, which allows diffusion and atom interlocking across the contact between two clean surfaces.
