Stress and strain localization three-dimensional modeling for particle-reinforced metal matrix composites

The ductility of particle-reinforced metal matrix composites (PR MMCs) is reduced by the localization of stress and strain, which is exacerbated by microstructural heterogeneity, especially particle clustering. Herein, the effect of particle distribution on the macroscopic and microscopic response has been studied using three distinct types of three-dimensional (3D) finite-element model: a repeating unit cell, a multiparticle model, and a clustered particle model. While the repeating unit cell model represents a cubic periodic array of particles, the multiparticle model represents a random distribution of particles contained in a cube of matrix material, and the clustered particle model represents an artificially clustered distribution of particles. These models were used to study the macroscopic tensile stress-strain response as well as the underlying stress and strain fields. The results indicate that a clustered microstructure leads to a stiffer response with more hardening than that of random and periodic microstructures. Plastic flow and hydrostatic stress localization in the matrix and maximum principal stress localization in the particles are significantly higher in the clustered microstructure. Damage is expected to initiate in the cluster regions leading to low ductility.