Stiffness of particulate reinforced metal matrix composites with damaged reinforcements

During tensile plastic deformation particulate reinforced metal matrix comp osites (MMCs) undergo reinforcement damage and a parallel reduction in stif fness. An analytical model is developed to calculate this stiffness reducti on using the equivalent inclusion technique proposed by Eshelby. The model considers both damaged and undamaged reinforcement particles as ellipsoidal inclusions but with different stiffness tensors. The effect of the aspect ratio of the reinforcing particles has been accounted for in the model. The model is very flexible and can meet different specific damage situations b y designing a suitable stiffness tensor for the damaged reinforcements. Fin ite Element analysis is used to modify a numerical stiffness tensor for cra cked reinforcement particles. The model is compared with an earlier model o f modulus reduction in MMC materials anal with a few experimental measureme nts made on a 15 vol.-%SiC particulate reinforced aluminium alloy 2618 MMC.