Recent progress in laser-assisted friction stir welding

The need for lightweight structures is becoming increasingly critical in our demanding world. Thus, high-quality joints in similar material combinations or hybrid metal structures are equally crucial for welding techniques. This implies that adding auxiliary assisting sources during the process can significantly mitigate the problems associated with inadequate softening, a known drawback of the friction stir welding (FSW) process. It has been discovered that laser beam preheating can soften the weld region of the workpieces when implemented in a pre-planned manner. Subsequently, it induces a temperature rise in the workpieces by enhancing their plasticization characteristics. A satisfactory laser beam induces changes in the materials’ condition, facilitating a more straightforward joining process than the traditional FSW process. Moreover, it is even easier to join aluminum alloys to other harder metals, e.g., steel or copper, let alone joining aluminum alloy, magnesium alloy, and nickel-based superalloy. This article presents the influence of incorporating a laser beam source as an auxiliary energy source during the FSW process. It discusses the most recent progress on changes in the behaviour of joints produced with and without laser beam sources, particularly in terms of temperature distribution, appearance, joint formation, microstructure, and mechanical properties. Furthermore, the benefits of laser-assisted FSW (LAFSW) joints compared to traditional FSW have been thoroughly highlighted.