Rearrangement densification in liquid-phase sintering

Grain rearrangement has a significant role in sintering densification when a liquid phase forms. Although grains may change shape, bringing the grain centers closer to each other and producing overall densification, this contribution is slow and localized to the grain contacts regions. On the other hand, the movement of individual grains through capillary force effects can provide a burst of rapid densification. To describe the spatial grain arrangement quantitatively, a new parameter is proposed, termed the grain-arrangement factor. An increase in the grain-arrangement factor indicates the microstructure is packing to a higher density. Analysis of the relations between this factor and other microstructure parameters provides an indirect method to measure the state of grain arrangement in liquid-phase sintering. Experiments performed on a tungsten heavy alloy show that the grain-arrangement factor mainly depends on the solid volume fraction and the dihedral angle.