Multi-particle FEM modelling on hot pressing of TiC-316L composite powders

Abstract

316L stainless steel (abbreviated by 316L) has been applied in many key industrial areas due to its outstanding properties like corrosion resistance, ductility and biocompatibility etc. However, the relatively low strength and wear resistance of this material restrict its further application. This problem can be solved by the introduction of TiC particulate reinforcement into 316L matrix, which can effectively improve the strength, stiffness, wear resistance and high temperature strength. In the present work, three-dimensional hot pressing (HPing) of TiC-316L composite powders in a closed die is numerically reproduced by multi-particle finite element method from particulate scale. The evolution of macro- and microscopic properties during HPing is systematically characterized and analyzed, and the densification dynamics and mechanisms are identified. The results show that HPing can not only significantly decrease the pressing pressure, but also alleviate the stress concentration in the final compacts. With the increase of pressing temperature, the equivalent von Mises stresses in the compacts get smaller and the equivalent strains of TiC-316L composite powders get larger. During HPing, the voids are mainly filled by particle rearrangement and plastic deformation of 316L particles. Meanwhile, the equivalent von Mises stresses concentrated within the 316L particles firstly increase and then decrease, and the equivalent von Mises stresses concentrated within the TiC particles increase monotonically. Large stresses are mainly concentrated within the TiC particles, which are decreasing from the surface to the center of each particle. Also, larger contact normal forces are mainly distributed within and around the TiC particles.