Comparison of the elastic and plastic behaviours of two interpenetrating phase composites with HCP inspired morphologies

摘要

The effect of phase morphology on the elastic and plastic behaviour of interpenetrating phase composites (IPCs) was investigated using finite element (FE) modelling. Two different microstructural morphologies were modelled, one consisting of a three-dimensional (3D) hexagonal arrangement of intersecting spheres of a stiff and strong phase with the interconnected interstitial spaces filled with a second phase, and the second representing a 3D hexagonal network of interconnected cylindrical rods of a stiff and strong phase surrounded by a second interconnected phase. The effect of morphology was assessed by studying the effective macroscopic behaviour calculated by the models and by examining the microstructural mechanisms underlying the macroscopic behaviour. The elastic and plastic properties were influenced by both the volume fraction and morphology of the stronger and stiffer phase, with phase morphology exerting an increasing influence as the difference between the mechanical properties of the phases increased and after yielding of the stronger phase. Observation of stress distributions showed that the availability, orientation and shape of a low-compliance path for stress transfer through the stiffer phase were important factors affecting the macroscopic properties. The morphology that minimized the development of stress concentrations along the low-compliance path developed superior mechanical properties. These findings can be of particular importance for the development of IPCs with tailored properties.