Probabilistic response of heterogeneous particle reinforced metal matrix composites with particle size dependent strengthening

This paper presents an enhanced continuum model for a heterogeneous particle arrangement to simulate the variability in the size dependent strengthening of silicon carbide (SiC) ceramic particle reinforced metal matrix composites (MMCs). The model incorporates a size dependent “punched” zone around the particles that is the result of a local increase in dislocation density during thermal processing due to geometrically necessary dislocations generated by the mismatch in coefficients of thermal expansion of the particle and matrix. In this work, these zones are explicitly accounted for in finite element simulations of multiple realizations of representative heterogeneous composite microstructures consisting of randomly distributed particles in a metal matrix. This modeling approach is used to capture the probabilistic response of the material which is linked to stochastic variations in the local microstructure of the material. The model is then used to explore the effects of particle size and volume fraction on the variability of the inelastic deformation response of heterogeneous MMCs. It is shown that the variance of the composite response increases as the particle size decreases and as the volume fraction of reinforcing particles increases. It is also shown that the amount of strain localization in the matrix increases as the particle size decreases.