TRANSITIONS IN THE ABRASIVE WEAR-RESISTANCE OF FIBER-REINFORCED AND PARTICLE-REINFORCED ALUMINUM

The resistance of metal matrix composites in two-body abrasive wear with silicon carbide and flint abrasives has been investigated. An alumina fibre-reinforced Al-Si1MgMn aluminium alloy with 10, 15 or 30 vol.% of short fibres and an Al-Si7Mg aluminium alloy reinforced with 10 or 30 vol.% of 20 mu m silicon carbide particles have been tested. The matrix hardness of the composites was varied by heat treatments. In previous work, it has been found that the reinforcement of aluminium alloys by particles or short fibres leads to significantly improved wear resistance in milder abrasive situations, while it gives no, or even negative, effect in tougher situations. Thus, transitions may occur from a wear mode resulting in beneficial effects of the reinforcement to one with low or negative effect. In this work special attention is paid to these wear transitions, in particular the effect of applied load on the transitions is systematically investigated. The results are compared with a theoretical model recently published by the present authors.