MODELING OF SUPERSOLIDUS LIQUID-PHASE SINTERING .1. CAPILLARY FORCE

Prealloyed powders subjected to supersolidus liquid phase sintering (S LPS) exhibit partial melting. A liquid phase forms along the grain bou ndaries, at the interparticle neck region, or on the particle surface. Densification involves an increase in the liquid volume fraction alon g with simultaneous coalescence of the particles. A two-particle model is developed that takes into account an increasing liquid content wit h coalescence, as well as a shape change of the merging particles (ini tially spherical). The variation in capillary force with processing pa rameters such as temperature and liquid volume fraction give improved predictions over prior models. The model predicts that the capillary f orce is affected strongly by the amount of liquid phase, wetting angle , and the shape of the coalescing particles.