MODELING OF SUPERSOLIDUS LIQUID-PHASE SINTERING .2. DENSIFICATION

Analogous to the viscous-flow principle in rheology, a densification m odel is developed for super-solidus liquid phase sintering (SLPS). The presence of a threshold value of the liquid film along the grain boun dary and its influence on the onset of densification is analyzed. The liquid film thickness is affected by the grain size and liquid volume fraction. Both change with temperature during constant heating, thereb y influencing the densification process due to particle rearrangement via grain fragmentation. Two cases of densification, one using a const ant heating rate and the other under isothermal conditions, are discus sed. The present model is in good conceptual agreement with the viscou s flow-induced densification mechanism and provides a sound basis for a quantitative study of shrinkage behavior in SLPS.