Computational investigation of microstructural effects on abrasive wear of composite materials

Abstract

Abrasive wear of composite materials is a complicated surface damage process, affected by a number of factors, such as microstructure, mechanical properties of the target material and the abrasive, loading condition, environmental influence, etc. Microstructure is one of the major factors; however, its effect on the wear mechanism is difficult to investigate experimentally due to the possible synergism with other influences. Computer simulation is an effective approach for such studies, since controllable “computational experiments” can be performed to investigate the separate contribution of the individual factors on wear. In this work, a dynamic model, based on the Newton's law of motion, was applied to simulate abrasive wear of hard particle reinforced metallic matrix composite materials. In the simulation, a material system is mapped onto a discretized lattice. Each lattice site represents a unit mass which may move under an external wearing force and through the interaction with adjacent sites. The site–site interaction is a function of the mechanical properties of the reinforcement and the matrix. When the strain of a site–site bond exceeds a critical value for fracture, the bond is broken. A lattice site or a cluster of lattice sites is worn away if all bonds connecting the site or the cluster to its neighbours are broken. Microstructure largely influences the wear behaviour of a composite material. When abraded by abrasive particles, the reinforcement volume fraction, size and its distribution play important roles in resisting abrasive wear. In the present study, the above-mentioned factors, especially the effect of the size distribution of reinforcing particles in a composite on wear, were computationally investigated. Furthermore, the effects of abrasive size and the ratio of the abrasive size to that of the reinforcement particles were also studied. Mechanisms responsible for the microstructural effects on abrasive wear of composite materials are discussed.