A Computational Study on the Effect of Initial Powder Packing Configuration on Final Sintered Part Microstructures

Author(s):

Brennan Watkins, Efrain Hernandez-Rivera, and Matthew Guziewski

Abstract:

Sintering processes are widely used for manufacturing parts from powders of different material classes (e.g., ceramics). Many component properties critical to performance (e.g., porosity) depend on the initial powder packing configuration, sintering time, temperature, and pressure. The relationship between the initial powder packing configuration and the final part microstructure are poorly understood, leaving much to be gained from a comprehensive computational investigation of the topic. Furthermore, a large-scale experimental study of the packing-microstructure relationship would be prohibitively costly and time-consuming to conduct, whereas detailed simulation of a wide array of packing situations and sintering conditions can be easily carried out. Initial powder packing configurations were created using discrete element modeling via the LAMMPS package, and a Monte Carlo-based sintering model was subsequently used to simulate the densification of the part. However, the accuracy and speed of these methods depend on parameters such as domain size, time step size, and discretization mesh density; accordingly, convergence tests are performed on both the powder packing model and the sintering model to determine optimal simulation parameters. These developments permit expedient and accurate simulation of both powder packing and sintering processes, allowing for prediction of final part microstructures from initial powder packing configurations.