Hot rolling behaviour of stir-cast Al 6061 and Al 6082 alloys – SiC fine particulates reinforced composites

Abstract

Rolling of wrought aluminium matrix composites with hard phase-reinforcements such as SiC, is interesting to produce sheets for engineering constructions due to their light weight combined with good strength and wear resistance. In this work, the hot rolling behaviour is studied for stir-cast composites with matrix of Al 6061 and Al 6082 alloys and fine SiCp particulates with size of 15 μm and 8 μm and volume fraction up to 30%. For composite casting, optimum casting procedures and materials pre-treatment has been applied for successful insertion of particles into the melt, better particles/matrix wetting and particles distribution, minimized SiC/Al reaction. From thermomechanical simulation, step rolling is defined to be suitable at a strain rate of 1 s −1 rate for each step, using intermediate heat treatment at 450 °C for a period of 10 s to 1 h. Generally, the quality of rolled product was improved with improving casting quality. Successive hot rolling resulted in decreasing void and the agglomeration clusters and hence enhanced mechanical properties are achieved. The flow behaviour under rolling of Al-particulate metal matrix composites, PMMCs, is analysed and the product is characterised for its mechanical properties.