Some issues on tailoring possibilities for mechanical properties of particulate reinforced metal matrix composites

The evolution of mechanical properties, for some aluminium matrix composites, as a function of the variation of particulate nature and content is reported. The composites were made by Vortex casting and based on a commercial aluminium alloy, with either single-phase or two-phase (hybrid) reinforcement. The reinforcing particles are graphite and silicon carbide, in volume fraction concentrations up to 10%. The mechanical properties were evaluated by hardness measurement and tensile tests, made according to the corresponding standards for metals, at room temperature. On the other hand, an investigation is made on the evolution of mechanical properties and wear resistance of the studied composites, in different conditions of heat treatments. The study suggests that the heat treatment has potential to produce a desired combination of properties in aluminium graphitic composites, by varying the treatment parameters (temperature and duration). By rigorously choosing the balance of the reinforcing phases, together with some technological parameters of the manufacturing process, it is possible to optimize the properties of metal matrix composites.