Abstract Friction stir welding (FSW), a mature solid-state joining method, has become a revolutionary welding technique over the past two decades because of its energy efficiency, environmental friendliness and high-quality joints. FSW is highly efficient in the joining of Al alloys, Mg alloys, Ti alloys, polymers and other dissimilar materials. Recently, FSW has gained considerable scientific and technological attention in several fields, including aerospace, railway, renewable energy and automobile. To broaden the adoption of FSW in manufacturing fields, three inherent issues—back support, weld thinning and keyhole defects—must be addressed to ensure the structural integrity, safety and service life of the manufactured products. This review covers the recent progress on the control strategies for these inherent issues, which are basically divided into self-supported FSW, non-weld-thinning FSW and friction stir-based remanufacturing. Herein, the aim is to focus on the corresponding technical development, process parameters, metallurgical features and mechanical properties. Additionally, the challenges and future outlooks are emphasized systematically.

中文翻译：

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搅拌摩擦焊固有问题控制策略的最新进展

摘要 搅拌摩擦焊（FSW）是一种成熟的固态连接方法，由于其节能、环保和高质量的接头，在过去的二十年来已成为一种革命性的焊接技术。FSW 在连接铝合金、镁合金、钛合金、聚合物和其他异种材料时非常有效。近年来，FSW在航空航天、铁路、可再生能源和汽车等多个领域获得了相当多的科技关注。为了扩大 FSW 在制造领域的采用，必须解决三个固有问题——背部支撑、焊缝变薄和锁孔缺陷，以确保制造产品的结构完整性、安全性和使用寿命。本综述涵盖了针对这些固有问题的控制策略的最新进展，基本上分为自支撑FSW、非焊缝减薄FSW和搅拌摩擦再制造。在此，重点关注相应的技术发展、工艺参数、冶金特征和机械性能。此外，系统地强调了挑战和未来前景。