Friction in abrasion of alumina fibre and silicon carbide particle reinforced aluminium

Abstract Two types of metal matrix composites have been tested regarding their friction properties in abrasion. Firstly, composites consisting of 10 or 30 vol.% silicon carbide particles in an AlSi7Mg aluminium matrix and secondly composites with 10 or 30 vol.% alumina fibres in AlSilMgMn aluminium have been evaluated. Also the unreinforced aluminium alloys were evaluated as reference. Silicon carbide and flint abrasives of different grit sizes were used in a pin-on-drum wear and friction tests set-up. The influence of applied load and matrix hardness was also systematically investigated. Special attention has been paid to how the coefficient of friction is changed in abrasion due to the reinforcement and the matrix hardness. It is shown that both fibre and particle reinforcements reduce the coefficient of friction in abrasion. The reduction of the friction is strongly dependent on the testing parameters. Generally, the coefficient of friction is reduced with increased amounts of reinforcements and with higher matrix hardnesses, but almost independent of the applied load and the type of abrasive. The reasons for the reduction in friction caused by the reinforcements and the correlation between the reduction in friction and wear rate caused by the reinforcement are discussed. It is believed that the load distribution over the phases in the contact zone is a crucial parameter which decides which phase will dominate the overall friction.