Impact strength of joints of aluminium matrix composite formed using friction stir welding technique

Abstract

Friction stir welding (FSW) is solid state welding technique. It is better process as compared to fusion welding processes. It is applied to weld different materials like aluminium, magnesium, steel etc. As demand and applications of metal matrix composites (MMCs) are continuously increasing due to their advantages, FSW process is widely applied to weld them. This study is being done to study the impact strength of joints of thin plates made up of aluminium matrix composites (AMCs) having 5% vol. of SiC particulates. Joints were prepared on conventional milling machine. The joints were fabricated at fixed tool speed by varying feed rate. Joints prepared were tested using charpy test to calculate impact strength. Impact strength of the welded joint was found to be 4 J at a feed rate of 20 mm/min while impact strength was further reduced to 2.8 and 2.6 J at feed rate of 25 mm/min and 35 mm/min respectively. It was also found that defect free joints can be obtained at lower feed rate. Lower feed rate gives sufficient time to heat work piece which raises its temperature and material gets softened. It results in proper plastic deformation and improves ductility of the work piece.