Influence of deep cryogenic and natural ageing treatment on Al 7068- Al2O3 metal matrix composites

Aluminium matrix composites are the leading materials in aerospace and automotive applications due to their excellent structural properties. Cryogenic and ageing are the heat treatment processes that are employed to improve the performance of aluminium alloy components. The present study details an experimental investigation on deep cryogenic treatment (DCT) and ageing heat treatment (AHT) of Al 7068 reinforced with Al2O3 under various weight propositions. The composites are developed using the stir-casting technique. The proportion of base and reinforcement materials is designed based on the percentage of reinforcement materials, such as 0%, 2%, 4%, 6%, and 8%. The DCT has been conducted at 77 K, and ageing has been conducted at 688 K (for 2 h) and 399 K (24?hours), followed by water quenching. The heat-treated samples were subjected to the tensile test, compression test, hardness test, and wear analysis. In addition to that, fractural and surface wear analysis is also carried out through scanning electron microscopy (SEM). The final results show that Al7068 with 6% Al2O3 reinforcement has a greater impact than other matrix combinations.