Aging response of aluminium alloy 2024/silicon carbide particles (SiCp) composites

The aging behaviour of AA2024/0, 8, 14, 19, and 24 vol.% SiCp composites was studied using the hardness Rockwell B and X-ray diffraction techniques. The composites were manufactured by stir-casting in the semi-solid state of the alloy AA2024 (compocasting). Aging of the composites and unreinforced alloy took place at 177 °C for a period of 2–200 h. Precipitation phases present were Al2CuMg for the unreinforced alloy 2024, and CuAl2, Mg2Si for the composites. Peak hardness increased as the SiCp volume fraction increased and appeared almost at the same time after about 14 h aging in all the materials. The hardness reduction rate in the overaged condition decreased with increasing SiCp content.