The minimum volume fraction of SiC reinforcement required for strength improvement of an Al-Cu based composite

Metal matrix composites (MMCs) represent a unique class of materials with an ability to blend the properties of the ceramics with those of metals/alloys. The incorporation of hard and brittle ceramics phase is widely carried out in order to improve on the strength and wear properties of metallic matrices. In related studies carried out on spray-processed materials, it was observed that the incorporation of the ceramic particulates need not always increase the strength of metallic matrix unless they exceed a certain critical volume fraction. In order to explain these rather unusual results, a theoretical model was formulated to determine the critical volume fraction that may be required in order to realize the improvement in the ultimate tensile strength of the metallic matrices. The model proposed here is based on the equivalent inclusion method as related to the micromechanics of composites. The results derived from the model are interpreted with a view to establishing the link between the theoretical results obtained with the experimental findings.