The influence of particle distribution on the mechanical response of a particulate metal matrix composite

A self-consistent model, based on Eshelby's equivalent inclusion method, has been developed to predict to flow of a particulate-reinforced alloy. The model gives excellent agreement with the measured elastic moduli for Al/SiC composites. Beyond the elastic limit, the model predicts an increase in the initial work hardening rate with increasing particle content. At large strains (above about 1%) the stress-strain behaviour of the composite is parallel to that of the unreinforced alloy. The results agree well with those obtained by Bao et al. [G. Bao, J. W. Hutchinson and R. M. McMeeking, Acta metall. mater.39, 1871 (1991)] using finite element methods, indicating that solutions based on average stress fields around particles do capture the essential features of composite strengthening. However, the current treatment can be readily extended to treat the effect of an inhomogeneous particle distribution on strength. As the degree of particle clustering increases, an increase in the rate of initial work hardening is predicted. Moreover, the strengthening ratio is increased substantially by clustering.