Effect of process parameter on microstructure and mechanical properties of friction stir welded Al-Li alloy 2050: state of the art review

Abstract Aerospace-grade aluminium-lithium (Al-Li) alloy 2050 is widely utilized due to its excellent strength-to-weight ratio, fatigue resilience, and corrosion resistance. However, the reactivity of lithium and the possibility of defects make welding this alloy challenging, especially with conventional joining techniques. Friction Stir Welding (FSW) has been shown to improve the mechanical characteristics and joint quality, providing a solution. This paper reviews the latest developments in the third generation of Al-Li alloys 2050 FSW and the heat generation relation with the tool during the joining process, focusing on process variables, mechanical performance, and microstructure. Additionally, it discusses the challenges and sensitivity of the process, guiding further research and practical applications in aircraft welding.