Effect of Particle Size Distribution on the Response of Metal-Matrix Composites

Abstract

AbstractAn enhanced continuum model for ceramic particle reinforced metal matrix composites (MMCs) is used to explore the effect of particle size distribution on the variability in deformation response of heterogeneous microstructures. The model incorporates particle size dependent strengthening through a “punched” zone around the particles that is the result of an increase in dislocation density 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 mesoscale finite element simulations of representative heterogeneous composite microstructures consisting of randomly distributed particles in a metal matrix. Additionally, particle-matrix interface decohesion is incorporated through the use of cohesive zones. The results demonstrate that in the absence of material failure, the mean particle size of a distribution is sufficient to predict the elastic–plastic response with nominal variance in the response of the composite. The effect of interface strength on particle stresses is quantified and shown to reduce particle fracture in distributions containing large particles.KeywordsMetal matrix compositeMMCModelingParticle reinforcement