Plasticity of Particle-Reinforced Composites With a Ductile Interphase

Abstract

A homogenization theory is developed to determine the overall elastoplastic behavior of a particle-reinforced composite with a ductile interphase. Unlike most existing homogenization theories which are primarily concerned with the ordinary two-phase composites, the present one is confronted with two ductile phases, with one enclosing the other. The theory is developed with the aid of a linear comparison composite using a field-fluctuation method to calculate an energy-based effective stress of the ductile phases. In order to examine its accuracy, an exact elastic-plastic analysis under dilatational loading is also developed, and it was found that, despite its simplicity, the theory could provide plausible estimates for the overall behavior of the three-phase composite. The theory is applicable to a composite system regardless whether the interphase is more ductile or stiffer than the matrix, and when the interphase is more ductile, it is shown that even the presence of a thin layer can have a very significant effect on the plasticity of the overall composite.