Simulation of the toughness of partially sintered ceramics with realistic microstructures

Increasing the pore volume fraction of porous ceramics enhances their functionality for a wide range of applications. However, the increased functionality comes at the expense of their toughness. Discrete element method (DEM) three-dimensional simulations, which operate at the length scale of individual particles, are used to investigate the toughness of microstructures typical of partially sintered ceramics. The method is first validated by comparing DEM simulations to the linear elastic fracture mechanics elastic solution at the crack tip of a pre-cracked numerical sample. The toughness of realistic random microstructures is then obtained using DEM simulations and compared to experimental data. Green density is shown to have a significant effect on toughness. Discrete simulations also suggest that the linear relationship between toughness and Young's modulus is primarily linked to the size of the solid necks formed during sintering of particles. (c) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.