Michael V. Braginsky

Modelling of anisotropic sintering in crystalline ceramics

We present a model that describes anisotropic shrinkage during sintering in a powder compact of aligned, elongated particles by deriving the anisotropic sintering stress and the anisotropic generalized viscosity as a function of material and geometric parameters. The powder compact consists of elongated particles, which are perfectly aligned and simply packed with elliptical pores at all the quadra-junctions between the particles. The model considers mass transport by grain boundary diffusion and surface diffusion. Shrinkage rates are calculated for a variety of geometries and are compared to kinetic Monte Carlo simulations.

An Experimental Validation of a 3D Kinetic, Monte Carlo Model for Microstructural Evolution during Sintering

An experimental validation of a 3D kinetic, Monte Carlo model for simulation of microstructural evolution during solid state sintering will be presented. The model – a statistical mechanical model, which can simulate curvature-driven grain growth, pore migration, and vacancy formation, diffusion and annihilation – is validated by comparing microstructural evolution obtained experimentally for a copper powder compact. The 3D microstructural evolution of copper powder particles sintering was imaged in-situ by microtomography. The images show particles with internal porosity percolating through the particles. Microstructural features – e.g., neck formation and growth – from the experimental images as well as the overall densification rates are compared to the simulations.