Tribological behaviour of AA 5083/Micron and Nano SiC composites fabricated by ultrasonic assisted stir casting process

Metal Matrix composites (MMCs) are light weight, high-strength materials with potential application in areas such as automobile, aerospace, defence and other industries. MMCs are projected to significantly reduce the overall weight of the vehicle and aircraft while maintaining satisfactory structural strength. Micron and Nano-sized ceramic particle reinforced aluminum matrix composites fabricated using conventional stir casting technique usually present poor distribution of these particles within the matrix and high porosity. In this study, AA 5083 alloy micron and nano SiC composites have been fabricated by Ultrasonic assisted Stir casting process. Different weight % of SiC particles Micron (10 wt%) and Nano (1, 2, 3, and 4 wt%) were used for synthesis of aluminum matrix composites. Scanning electron micrographs show uniform distribution of SiC particles however with agglomeration at some places. An attempt has been made to study the influence of wear parameters like applied load, sliding speed, sliding distance and percentage of reinforcement on the dry sliding wear behaviour of aluminum matrix micron and nano SiC composites. Results revealed that at low load and smaller sliding distance composites with nano SiC show higher wear resistance; however at high load and longer sliding distance composites with micron SiC shows higher wear resistance among all composites tested. The application of ultrasonic vibration on the composite during melting not only refined the grain structure of the matrix, but also improved the distribution of nano-sized reinforcement.