A study on the simulation of metal powder molding based on the discrete element method with equal particle size

Metal powder pressing is an important key process in the field of powder metallurgy, and the densification process and the degree of densification are affected by factors such as powder properties, die parameters, and the pressing process. Since it is difficult to accurately calculate the number of powder particles by traditional methods, a multi-particle model combining the discrete element method (DEM) and the finite element method (FEM) is used in this study to analyze the effects of the powder stacking structure, the metal composition ratio, the pressing force, the holding time, and the friction coefficient of the inner wall of the die on the densification process. In the modeling process, each powder particle is treated as an individual and represented using the von Mises yield function and Cauchy stress. In this paper, the bi-directional compression molding process and micromechanical behavior of monometallic copper powders and copper–aluminum composite powders with the same particle size are simulated using a coupled DEM–FEM method, which remedies the lack of research in this field. First, the micromechanical behaviors of the particles during compression molding are elucidated, including shape evolution, stress distribution, and force-chain dynamics; second, the effects of aluminum content, initial packing density, and die-wall friction on densification are quantified; and then the models are validated based on empirical formulas (e.g., Hecke’s and Huang Peiyun’s equations). By sharing multi-scale simulations with parametric analysis and combining theoretical modeling with practical industrial applications, the densification mechanism of composite metal powders is dissected, which provides a sizable example for process optimization.