An overview on joining of aluminium and magnesium alloys using friction stir welding (FSW) for automotive lightweight applications

Lightweight structures are increasingly in demand in the automotive manufacturing industry for fuel economy, vehicle efficiency and meeting reduction in emissions regulations. Weight reduction in automobiles have been achieved traditionally by reducing the body panel steel-sheet thickness and increasing its strength, but this technique is faced with the challenge of reduced stiffness in the panels. In the bid to incorporate numerous light-weighting ideas in manufacturing, the replacement of steel with light metals has been considered. Aluminium and magnesium are alternative materials that could be used to substitute steel because they are both lighter and possess comparable structural characteristics. Aluminium and magnesium has a density of 2.7 g cm(-3) and 1.74 g cm(-3) respectively compared to steel density of 7.86 g cm(-3). However, there is usually unavailability of aluminium for high-volume production. Hence, the joining of aluminium to magnesium in the right proportion could be suitable as potential materials for new automobile applications to mitigate the challenges faced with the usage of steel and availability of aluminium and help to further reduce the vehicle weight. This study focuses on a review of the basis and joining of aluminium and magnesium alloys through friction stir welding to derive insights on appropriate joining process parameters selection.