Abstract Friction stir spot welding (FSSW) is a variation of linear Friction Stir Welding (FSW), which was invented to compete with resistance spot welding (RSW) and riveting of lightweight alloys in the automobile, shipbuilding and aerospace industries. Recently, the application of FSSW has rapidly extended to a variety of metals and nonmetals. This article provides a comprehensive review of the recent progress on the process fundamentals, parameters optimization, microstructural evolution and mechanical properties, and relevant simulation and modeling of FSSW. The article also evaluates the energy generation, temperature distribution, plastic flow and joining mechanisms. The optimizations of tool design and welding parameters are obtained through experiments and modeling. Furthermore, a particular emphasis is given to microstructural characterization of the recovery, recrystallization and grain growth, and related annealing phenomena after in the welded alloys. The mechanisms of defect formation and liquidation cracking are discussed in detail. The mechanical properties, including hardness, static strength, fatigue performance and failure mechanisms and the relationship between mechanical properties and microstructures are also addressed along with residual stress and corrosion behavior.

中文翻译：

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搅拌摩擦点焊技术进展

摘要 搅拌摩擦点焊 (FSSW) 是线性摩擦搅拌焊接 (FSW) 的一种变体，它的发明是为了在汽车、造船和航空航天工业中与电阻点焊 (RSW) 和轻质合金铆接竞争。近年来，FSSW 的应用迅速扩展到多种金属和非金属。本文全面回顾了 FSSW 在工艺基础、参数优化、微观结构演变和机械性能以及相关模拟和建模方面的最新进展。文章还评估了能量产生、温度分布、塑性流动和连接机制。工具设计和焊接参数的优化是通过实验和建模获得的。此外，特别强调了焊接合金中恢复、再结晶和晶粒生长以及相关退火现象的显微组织特征。详细讨论了缺陷形成和液化开裂的机制。机械性能，包括硬度、静态强度、疲劳性能和失效机制以及机械性能和微观结构之间的关系，以及残余应力和腐蚀行为也得到了解决。