Finite element analysis of observed high strengthening in composites with regularly segregated microstructures

Abstract

A distinct dual phase composite has been developed, comprising spherical reinforcement clusters and an unreinforced matrix, according to numerical simulation of crack initiation and propagation in discontinuously reinforced MMCs. The present work is aimed at interpretation of the high strengthening ratios which were actually measured in such dual phase composites. Elastic-plastic finite element modelling is utilised to analyse the strengthening ratio in a two-dimensional idealised microstructure with periodic clustering. As the degree of clustering increases, the strengthening ratio is predicted to increase. In composites with a networking cluster, much more strengthening is exhibited together with relatively uniform strain distribution. The primary mechanism leading to additional strengthening due to clustering derives from an optimum ratio in deformation resistance between a matrix and a reinforcing phase. In the proposed dual phase composites, each cluster can behave as a single reinforcement which can deform plastically and there is no distinct interface between the cluster and the softer phase.