Xizhong An

By Xizhong An, Yu Liu, Fen Huang and Qian Jia

Uniaxial die compaction of two-dimensional (2D) Al/SiC core/shell (core: SiC; shell: Al) composite powders with different initial packing structures was numerically reproduced using DEM-FEM coupled MPFEM modeling from particulate scale. The effects of external pressure, initial packing structure, and SiC content on the packing densification were systematically presented. Various macro and micro properties such as relative density and distribution, stress and distribution, particle rearrangement (e.g. sliding and rolling), deformation and mass transfer, and interfacial behavior within composite particles were characterized and analyzed. The results show that by properly controlling the initial packing structure, pressure, and SiC content, various anisotropic and isotropic Al/SiC particulate composites with high relative densities and uniform density/stress distributions can be obtained. At early stage of the compaction, the densification mechanism mainly lies in the particle rearrangement driven by the low interparticle forces. In addition to sliding, accompanied particle rolling also plays an important role. With the increase of the compaction pressure, the force network based on SiC cores leads to extrusion on Al shells between two cores, contributing to mass transfer and pore filling. During compaction, the debonding between the core and shell of each composite particle appears and then disappears gradually in the final compact.

Part of the book: Powder Technology