Direct Multiscale Modeling of Diffusion Sintering of Ceramic Composites

Abstract

A new macroscopic sintering modeling approach is proposed. In modeling, each macroscopic element has a corresponding unit cell defined at the mesoscopic structure level of powder particles. Numerical modeling is carried out in parallel both at the structure level of unit cells and macroscopic level. The new approach does not use any macroscopic constitutive equations in analytical form but rather derive them by the homogenization over corresponding unit cells at every time step. This approach permits increasing the number of internal parameters in sintering models and considering the effect on sintering kinetics of parameters such as grain and pore size distribution and anisotropy. Free sintering of ceramic matrix composites with great inert inclusions is modeled as an example. It is shown that the modeling and experimental results agree if shear-induced dilatansion of ceramic-matrix powder during sintering is assumed.