Phase-field simulation of solid state sintering

Manufacturing materials for high performance applications with tailored properties requires a deep knowledge about the sintering process and especially the underlying microstructure evolution. Due to the complex interplay of the material and process parameters as well as complex geometries it is challenging to predict the microstructure evolution during sintering with analytical models. A phase-field model based on the grand potential approach considering volume, surface and grain boundary diffusion is presented to describe the microstructural evolution during solid state sintering. To efficiently investigate realistic green bodies with multiple thousand particles in three dimensions, the model is implemented in a highly optimized manner in the massive parallel phase-field solver framework Pace3D. By comparing the neck growth rates and the particle approach in a two particle system for the different diffusion mechanisms a good agreement to analytic solutions is found. Based on a three dimensional green body of 24897 Al2O3-grains the densification is investigated with respect to the dominant diffusion mechanisms and compared with the analytic Coble model. Finally, the appearance of isolated pores in the microstructure is discussed.