A MODEL FOR THE ABRASIVE WEAR-RESISTANCE OF MULTIPHASE MATERIALS

A theoretical model for estimating the abrasive wear resistance of multiphase materials and composites from the wear resistance of the constituents is proposed. Starting from Archard's equation, two rules for the dependence of the amount of reinforcing phase, corresponding to two wear modes, have been derived. These rules of mixture, constitute estimations of the upper and lower limits for the wear resistance of a composite. The theory also results in two corresponding formulations of the wear equation generalised to multiphase materials. The applicability and limitations of the theory are discussed. The validity of the theory is supported by results from two test series. Three-body abrasive tests with silicon carbide abrasives were performed on simple specially fabricated model composites and silicon carbide particle-reinforced aluminium alloy composites were tested in two-body abrasion against silicon carbide and flint abrasives. The model serves to clarify the roles of the matrix and the reinforcing phase of a composite in resisting wear. The model can be instrumental in estimating upper and lower limits of wear and in indicating how to redesign a composite or modify a triosystem (changing load, filtering abrasive particles, etc.) to transform the wear of a multiphase material towards the least severe mode.