Experimental investigation characterisation mathematical modelling and uncertain response prediction on friction stir welding of AA2014 alloy under n MQL condition

Abstract

Materials with a unique combination of high strength and low density are essential in producing high strength components such as skins and frames in the aerospace and defense industry. The desirable combination is found in AA2014 alloy, a precipitation-strengthened Al-Cu alloy, that is widely employed for its high strength to weight ratio. However, its application is limited only to structural components since joining AA2014 alloy through fusion welding processes causes defects such as hot cracking and porosity. Friction Stir Welding (FSW) is employed to overcome these defects and expand its application to complex structures of landing gear hub and aircraft engine components. FSW is a green technology that utilises a third body (a rotating tool) moving transversely across the junction of the two materials. The friction generated from the tool movement creates heat that binds the materials together. Nonetheless, the excess heat generated dissolves the strengthening precipitates of AA2014 alloy and causes reprecipitation of weaker phases thereby reducing the weld strength. Therefore, it is essential to remove the excess heat through external cooling techniques. The conventional flood cooling techniques employed in FSW consume a large amount of coolant and require specialized equipment to recycle and reuse, resulting in high energy consumption. The consumption of large amount of coolant is detrimental to the economy, environment and workers health. Therefore, it is the need of the hour to employ a sustainable cooling technique in FSW. newline