Effect of volume fraction of ceramic particulates on the ultimate tensile strength of an Al-Cu based metal matrix composite

Metal matrix composites (MMCs) represent a unique class of materials with an ability to blend properties of the ceramics with that 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 may 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 is formulated in the present study 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 establish the link between the theoretical results obtained with the experimental findings.