Strain gradients and continuum modeling of size effect in metal matrix composites (Q1357317)

The authors present the constitutive modeling for the particle size effects on the strength of particulate-reinforced matrix composites. The approach is based on a gradient-dependent theory of plasticity that incorporates strain gradients into the expression for the flow stress of matrix materials, and on a finite unit cell technique that is used to calculate the overall flow properties of composites. The authors show that the strain gradient term introduces a spatial length scale in the constitutive equations for composites, and the dependence of the flow of the stress on the particle size can be obtained. Moreover, a non-dimensional analysis along with the numerical results yields an explicit expression for the strain gradient coefficient in terms of the particle size, strain and yield stress. The authors present calculations for aluminum matrix composites with ellipsoidal particles and compare numerical results with experimental data.