Computer simulation of solution and growth processes during the initial stage of liquid phase sintering of tungsten heavy metal

Abstract

In the initial stage of liquid phase sintering, particle dissolution and growth processes occur. The melting matrix penetrates the solid particle agglomerates. A fraction of the particles dissolves in the liquid matrix phase and the original powder size will initially be reduced. At the same time the agglomerates of particles are effectively separated. In a second stage larger particles grow in equilibrium with the matrix, whilst smaller, pure particles dissolve into the matrix and the mean particle size increases. When an equilibrium is reached, the solid particles start to grow in the liquid matrix phase in accordance with the ripening process. The initial stages of liquid phase sintering have been investigated by short time sintering under microgravity and are presented in a series of micrographs. Mathematical models for the 3 stages have been developed.Computer simulations of these different stages in the solution and growth processes have been used to visualise the change in particle size distribution.