Sintering of regular two-dimensional arrays of particles surface and grain boundary diffusion

Abstract

The times required for sintering of regular arrangements of circular (cylindrical) particles surface and grain boundary diffusion have been evaluated using a precise two-dimensional numerical model. The influence of the dihedral angle and the grain boundary-to-surface diffusivity ratio have been examined. The sintering kinetics show the typical three stages, namely, fast sintering, followed by a stage of slow sintering and, finally, fast sintering near the point of final pore collapse. Following W. W. Mullins (1993, Scripta Matall. Mater. 29, 491), a simplified analysis assuming quasi-equilibrium pore shapes is carried out and discussed in terms of the full numerical model. By modelling different regularly packed particle arrays, the influence of initial density on the sintering kinetics is also evaluated. Not surprisingly, the densification time increases dramatically as the initial packing density decreases.