Influences of particle shape, volume fraction and matrix materials on the compressive behavior of MMCs

The compressive plastic deformation of particle-reinforced metal-matrix composites was investigated through numerical modeling at high strain rates. The numerical modeling is performed using the axisymmetric unit cell model, with the particles treated as elastic ellipsoids or cylinders embedded within a viscoplastic matrix. Five particle volume fractions from 10% to 50% and three aluminum matrix materials LY12CZ, LC4 and 7075 were analyzed. The results show that the flow stress increases with the increase of the strain rate and the volume fraction of the reinforcement. The flow stress increases more for the higher strain hardening matrix material and for the cylindrical reinforcement. The strain rate sensitivity is also related to the matrix material and the particle shape. A simple analytical model is introduced, which is able to describe the features of the computational predictions to a certain extent, which is in good agreement with the experimental results.