Micromechanics of formation and shrinkage of a closed pore in sintering by coupled grain boundary/surface diffusion

The microscopic principle of the stress-assisted sintering is that the relative velocity between two adjoining particles is proportional to the sum of the sintering force and the mechanical force transmitted by the contact. Here, we simulated sintering of four particles by coupled grain boundary diffusion and surface diffusion, in order to analyze how the sintering force varies with the evolution of particle shape, i.e., pinch-off of pore channel, formation and shrinkage of a closed pore. The shrinkage rate of the pore volume was proportional to the relative velocity of particles, then, to the sintering force. We discussed the effect of mechanical stress on sintering also.