Grain Growth and Mechanical Properties of Spray Formed Al/SiC Composites

摘要

The objective of this work was to evaluate the grain growth behaviour and mechanical properties of metal matrix composites. The material was produced elsewhere by spray forming of an aluminium alloy AA 7475 and co-depositing silicon carbide particles (20 vol%). The micro structure was evaluated in the as received condition and after a series of heat treatments, annealing, ageing and overageing. Optical microscopy was used to characterise the composite microstructure. Hardness measurements and tensile testing assessed the mechanical properties. Accentuated grain growth occurred due to the solution heat treatment and subsequent ageing and overageing did not produce further changes in grain size. The hardness peak was attained after heat treatment of the composite at 150 □C for 10 hours. Ageing the composite at 120 □C for 24 hours lead to higher tensile strength.