Numerical modeling and failure evolution of microstructure-based in-situ TiB2 and TiC+TiB2 reinforced Cu matrix composites

Abstract

The optimal design of microstructure is the key to further improve the properties of particle reinforced metal matrix composites. In this study, in-situ TiB2 and TiC + TiB2 reinforced Cu matrix composites are used as examples to develop the microstructure-based representative volume element models to describe their damage evolution and strengthening mechanisms. The most critical features including size distribution and morphology of the particles as well as the fracture of metal matrix, brittle damage of ceramic particles and traction-separation debonding of the interface were integrated into the modeling. Simulation results show that the model could well predict the performance of the composite and reveal its damage mechanism. When the particle size is normally distributed, the composite exhibits higher strength due to the size effect of different particles, which is more consistent with the experimental result. Both matrix and ceramic particles in mixed-phase particle reinforced metal matrix composites can be subjected to higher stresses, which results in higher strength of (TiC + TiB2)/Cu composites. Additionally, the spherical TiC particles facilitate the relaxation of stress concentration within the composite, resulting in a synergistic enhancement of strength and ductility. Under compression, localized interface damage first appears around the sharp corners of the hexagonal particles and induces crack initiation toward the matrix. These microcracks are interconnected and propagate along the direction of high stress, eventually leading to the failure of the composite. This work provides the basis and new ideas to reveal the failure mechanism of composites and further optimize their configuration design.