Advances in friction stir welding of titanium alloys: a comprehensive review

Titanium (Ti) alloys are widely used in industrial manufacturing, healthcare, transportation, and other sectors. However, due to significant variations in their physical and chemical properties when welded with other alloys, cracks are likely to develop in the joints, making it difficult to achieve stable welds. Key aspects of these processes include residual stresses, processing windows, temperature, material flow, welding tool wear, and design considerations. Particular emphasis is placed on the relationship between microstructure and resulting properties. This review aims to present current research and applications while providing a comprehensive overview of recent advancements in the welding and joining of titanium and light alloys. Various welding techniques such as fusion welding, brazing, friction welding, and reactive joining have been explored for titanium and light alloys. Among these, friction stir welding (FSW) of titanium alloys is the primary focus of this study, with special attention given to tool design, welding parameters, and weld strength.