Dry sliding wear behaviour of co-continuous ceramic foam/aluminium alloy interpenetrating composites produced by pressureless infiltration

Metal–ceramic interpenetrating composites (IPCs) consist of 3D-continuous matrices of discrete metal and ceramic phases. The goal is to develop superior multifunctional properties compared with traditional MMCs with a view to using these composites in applications including wear resistance, electrical components and light weight structural parts in industries including aerospace, automotive and defence, amongst others. In this paper, a pressureless infiltration technique was used to produce IPCs by infiltrating molten aluminium alloys into a range of gel-cast ceramic foams produced from alumina, mullite, and spinel. Processing conditions for different material systems were determined. The wear rates of the composites were measured under dry sliding conditions. The wear mechanism was investigated and the effects of the foam density and cell size on the wear properties were determined. It was found that the alumina or spinel reinforcement-based IPCs performed better than those based on mullite. It was also found that all the foam-based IPCs were up to twice as wear resistant as MMCs made by infiltrating a bed of ceramic powder

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► Interpenetrating composites of Al with oxide ceramics made by pressureless infiltration.
► Wear of IPCs transit from “running-in” stage to “steady state”.
► Higher ceramic content and medium cell size yield better wear resistance.
► Alumina and spinel are better than mullite as reinforcements resisting wearing.
► Ceramic foam-based IPCs are twice as wear resistant as ceramic powder-based AMCs.