An analytical study on strengthening of particulate reinforced metal matrix composites

Abstract

The relative importance of the load bearing effect of the reinforcement compared to the matrix-strengthening by the enhanced dislocation density in improving the yield strength of Metal Matrix Composites (MMCs) is studied. Nardone-Prewo's equation based on Modified Shear Lag theory is used for estimating the enhanced matrix strength but appropriately incorporating the effect of the matrix strengthening as well. The analytical estimation uses a Composite Sphere Model and involves the determination of the dislocation density of the matrix based on the effective plastic strain arising due to the thermal residual stresses. This presentation includes a systematic study of the dependence of the thermal residual stresses as well as the dislocation density on the volume fraction and the particle size of the second phase. The strength predicted in this study compares favourably with a few published experimental data.