AN ANALYTICAL STUDY ON STRENGTHENING OF PARTICULATE-REINFORCED METAL-MATRIX COMPOSITES

The relative importance of the load bearing effect of the reinforcemen t compared to the matrix-strengthening by the enhanced dislocation den sity in improving the yield strength of Metal Matrix Composites (MMCs) is studied. Nardone-Prewo's equation based on Modified Shear Lag theo ry is used for estimating the enhanced matrix strength but appropriate ly incorporating the effect of the matrix strengthening as well. The a nalytical estimation uses a Composite Sphere Model and involves the de termination of the dislocation density of the matrix based on the effe ctive plastic strain arising due to the thermal residual stresses. Thi s presentation includes a systematic study of the dependence of the th ermal residual stresses as well as the dislocation density on the volu me fraction and the particle size of the second phase. The strength pr edicted in this study compares favourably with a few published experim ental data.