Numerical Study of Residual Stress Effects on Deformation and Fracture in Metal Matrix Composites

Composite materials used in various industries possess pronounced microstructural heterogeneity characterised by the difference in thermomechanical properties of the constituents and the presence of interfaces of different scales and geometries. In this study, the deformation and fracture of an aluminium alloy with a metal matrix composite coating under thermomechanical loading are numerically investigated at the micro-, meso- and macroscales. Complex microstructure of the composite material corresponding to the experimentally observed one is taken into account explicitly in the calculations. The constitutive equations for an isotropic elastic-plastic Al6061T6 matrix and elastic-brittle boron carbide particles are integrated into the ABAQUS/Explicit software package via user-defined subroutines. An energy-based fracture criterion formulated in terms of equivalent stresses is used to take into account the fracture of ceramic particles in local regions of tension or compression. The influence of residual stresses on the composite macroscopic strength, plastic strain localisation in the aluminum matrix and crack initiation and propagation in the particles is investigated under uniaxial tension or compression of the composite, with the volume fraction of particles in the coating being varied.