Modeling solid-state sintering with externally applied pressure: a geometric force approach

Abstract

Solid-state sintering is one of the most widely used material processing technologies in modern manufacturing. The preponderance of previous computer simulations focused on free sintering (without externally applied pressures), in which the morphology evolution and densification in the system are driven by surface energy reduction. In this work, we develop an efficient algorithm to simulate solid-state sintering with hot pressing by explicitly considering interfacial diffusion as well as rigid body movement under external pressure. Particle movements including both translations and rotations are taken into account in the model, which are directed by the associated local stress state in the sintering system. A novel “geometric force” is also introduced to stochastically model geometrically necessary plastic deformations of the sintering particles to accommodate the initial fast densification due to the applied pressure. Subsequent evolution of the overall morphology and inter-particle connections are mainly controlled by interfacial energy minimization, while coarsening is considered in the later sintering stages. The utility of our method is illustrated by sintering 2D compacts of polydisperse circular particles and equal-sized elliptical particles. Significant coarsening occurs in the polydisperse particle system, while no significant grain growth is observed in the equal-sized ellipse system.