STRENGTHENING MECHANISMS OF METAL MATRIX COMPOSITES

Strengthening mechanisms of metal matrix composites (MMCs) are discussed from the viewpoint of both macro-and nano-level models. The macro-level models are law of mixtures and shear lag models, which are reasonably adequate for explaining the strengthening of aligned fiber (continuous and short) MMCs. While the nano-level models are based on dislocations (punching and back stress) and are found to explain well the strengthening observed in particulate MMCs. In both macro-and nano-level models, the residual stresses induced due to the CTE mismatch strain play an important role in influencing the yield stress of the composites.