3D DEM investigation on percolation of lubricant particles during uniaxial metal powder compaction

Based on the discrete element method, a 3D particle size model including MoS₂ lubricant and iron powder particles has been used to simulate the powder compaction process. The percolation behavior of sidewall lubricant particles and the influence of lubricant percolation on the powder densification and force chain parameters (quantity, average length, average strength, and angle) has been studied. Results indicated that the degree of percolation increased with the increase in pressure. Lubricants located at the top of the model are more prone to percolation. The lubricant percolation behavior causes the pores in the compact to become larger, and minimize the coordination number and compactness of the compact. Although the percolation behavior can generate more high-strength short force chains, it can lead to a high concentration of spatial angles of the force chains, hindering the formation of cross force chain networks.