Microstructure evolution during sintering: discrete element method approach

We present a new numerical model describing the transformation of a powder of crystalline particles into a dense poly-crystalline material. It is based on the key phenomena of sintering: shrinkage and grain coarsening driven by the minimization of the free energy. Representing each grain by a truncated sphere, the model takes into account the complex and changing shape of grains for determining the thermodynamic driving forces and associated kinetic coefficients. We validate the model by comparing the temporal evolution of a system of four particles with that obtained from a mesh-based method. We performed simulations on polydisperse packings of up to 16,000 particles. Using material and process parameters from the literature, the model accurately reproduces experimental data on the evolution of the grain size distribution for alumina.

Automated summary

We propose a new numerical model that accurately describes the transformation process of crystalline powder into dense poly-crystalline material. It considers the key phenomena of shrinkage and grain coarsening in sintering, driven by minimizing the free energy. The model represents each grain as a truncated sphere and takes into account the complex and changing shape of grains to determine thermodynamic driving forces and kinetic coefficients. Through validation with experimental data and comparisons with mesh-based methods, the model demonstrates its accuracy and ability to reproduce grain size distribution evolution.