Micro mechanical predictions of fatigue life for metallic matrix composites

A new incremental method is proposed to predict the cyclic behavior of metal-matrix composites. In each incremental step, the matrix is considered to be an anisotropic material whose stiffness tensor is chosen as the tangent moduli of the studied matrix. The Eshelby tensor for an ellipsoidal inclusion embedded in an anisotropic matrix is calculated numerically. With the aid of Mori-Tanaka mean field theory and numerical solution of the Eshelby tensor, the incremental stress and strain relation of the composite is derived. With the aid of the matrix mixed hardening law and the matrix fatigue properties, the tensile, cyclic hardening behavior and the fatigue life for a particulate reinforced composite are analyzed; the predicted results agree quantitatively well with the ones given in the literature. Finally, the method is applied to predict the fatigue life for metal matrix composites. The comparison with experiment is also given.