AkJminum allays containing silicon, copper, iron and nickel have been rubbed against steels of different hardness and al~ a grey cast iron. In all cases both oxidative and metallic wear occurs. The transition load between oxidative and metallic wear is increased as the silicon content increases and the addition of copper al~ brings about significant increases. The presence of copper is beneficial irrespective of its effect on the mechanical properties produced by solution treatment and ageing. In oxidative wear. transfer of iron from the counterface to the aluminum alloy occurs and a very complex surface containing AIFe and a AI203 is produced. Wear in the oxKfative regime occurs by fractUre and spal領 of the oxide from the aluminum allay surfure. Metallic wear occurs by plastic defor-ation, fractUre and metal transfer of aluminum to the surface of the steel counterface.Wear behavior of these alloys is not related in any way to their bulk mechanical propenies or microstructure. Considerable further effon is required before our knONledge of surfaceproperties is sufficient to design improved we.resistant alloys for engine components. TE 99 通用摩擦磨損試驗機