Cold rolling and mechanical properties of particle reinforced aluminum composites

Cold rolling and subsequent annealing processes were investigated to fabricate SiC particle reinforced pure aluminum composite sheets. Composite bars with different volume fractions of particles were prepared by a powder extrusion and cold rolled in various reductions and subsequently annealed at various temperatures. The limit rolling reduction, that is the maximum reduction at which no cracks are observed in the rolled sheet, was measured for the composites. The effects of cold rolling reduction and annealing temperature on the tensile properties of the composite sheets were evaluated and compared with those of unreinforced pure aluminum sheets. The composite sheet with a lower SiC volume fraction than 10% can be successfully cold rolled in higher reduction than 90%. The proof stress and tensile strength of the composite sheets rolled in higher reduction than 60% are hardly changed with the rolling reduction, though those of the unreinforced pure aluminum sheets are increased with the reduction. The proof stress and tensile strength of rolled pure aluminum are rapidly decreased and its elongation is rapidly increased by subsequent annealing at 548 similar to 573 K. But those properties of the composite sheets are only gradually varied with subsequent annealing temperature.