Effect of Composition, Particle Size, and Heat Treatment on the Mechanical Properties of Al-4.5 wt.% Cu Based Alumina Particulate Reinforced Composites 980700

The quest for higher efficiency and performance of automotive vehicles requires application of materials with high strength, stiffness and lower weight in their construction. Particulate-reinforced aluminum-matrix composites are cost-competitive materials, which can meet these requirements. MMCC, Inc. has been optimizing particulate-reinforced alloy systems and developing the Advanced Pressure Infiltration Casting (APIC™) process for the manufacture of components from these materials. This paper discusses the results of a recent study in which composites reinforced with 55 vol.% alumina were cast using two sizes of alumina particulate and eight different matrix alloys based on Al-4.5 wt.% Cu with varying amounts of silicon and magnesium. Optimum heat treatments for each alloy were determined utilizing microhardness studies. The tensile strength and fracture toughness were evaluated as a function of alloy chemistry, particulate size, and heat treatment. MMCC has used one of these composite materials, 2214/Al₂0₃-55p/T6, to cast composite brake calipers and connecting rods that provide significant weight savings over their ferrous counterparts.