Deep Cryogenic Treatment effects on wear properties of AA6061 Metal Matrix Composites

The application of Deep Cryogenic Treatment (DCT) has been widely tested on steels, with particular focus on machine tools for increasing hardness and resistance to wear. Currently, the focus is moving towards application of DCT on light alloys and Metal Matrix Composites (MMC) in order to investigate potential benefits with respect to the base material properties. In this study, the wear properties of Aluminium alloy (AA6061) matrix composites subjected to DCT are experimentally investigated and compared to the conventionally treated material. AA6061 properties include its structural strength and toughness, its good surface finish, its good corrosion resistance to atmosphere and sea water, its machinability, and its ability to be easily welded and joined. It is one of the most used light alloys, including application for vehicle body panels and chassis, driveshafts, brake components, fasteners and fitting, sheet metal work. Specimens based on AA6061 matrix reinforced with different combination of commercially available fly ash, Silicon carbide particles (SCP), whiskers (SC9M) and fibres (SCF7M), Molybdenum disulphide (MOS2) and Tungsten disulphide (WS2) were manufactured using stir casting process. Reciprocating and continuous pin-on-disk tests (Fig. 1) were performed at different levels of load and speed according to ASTM G-99 standard. Wear and friction coefficients were evaluated and wear tracks were compared through optical microscopy.