Friction stir welding (FSW), a highly efficient solid-state joining technique, has been termed as “green” technology due to its energy efficiency and environment friendliness. It is an enabling technology for joining metallic materials, in particular lightweight high-strength aluminum and magnesium alloys which were classified as unweldable by traditional fusion welding. It is thus considered to be the most significant development in the area of material joining over the past two decades. Friction stir processing (FSP) was later developed based on the basic principles of FSW. FSP has been proven to be an effective and versatile metal-working technique for modifying and fabricating metallic materials. FSW/FSP of aluminum alloys has prompted considerable scientific and technological interest since it has a potential for revolutionizing the manufacturing process in the aerospace, defense, marine, automotive, and railway industries. To promote widespread applications of FSW/FSP technology and ensure the structural integrity, safety and durability of the FSW/FSP components, it is essential to optimize the process parameters, and to evaluate thoroughly the microstructural changes and mechanical properties of the welded/processed samples. This review article is thus aimed at summarizing recent advances in the microstructural evolution and mechanical properties of FSW/FSP aluminum alloys. Particular attention is paid to recrystallization mechanism, grain boundary characteristics, phase transformation, texture evolution, characteristic microstructures, and the effect of these factors on the hardness, tensile and fatigue properties as well as superplastic behavior of FSW/FSP aluminum alloys.

中文翻译：

---

铝合金搅拌摩擦焊/加工的最新进展：显微组织演变和力学性能

搅拌摩擦焊接（FSW）是一种高效的固态连接技术，由于其节能和环保的特性而被称为“绿色”技术。这是一种用于连接金属材料（尤其是轻质高强度铝和镁合金）的使能技术，这些材料被传统的熔焊分类为不可焊接。因此，这被认为是过去二十年来材料连接领域最重要的发展。后来根据FSW的基本原理开发了搅拌摩擦加工（FSP）。FSP已被证明是一种用于改性和制造金属材料的有效且通用的金属加工技术。铝合金的FSW / FSP引起了相当大的科学技术兴趣，因为它具有革新航空航天，国防，海洋，汽车和铁路行业制造工艺的潜力。为了促进FSW / FSP技术的广泛应用并确保FSW / FSP组件的结构完整性，安全性和耐用性，必须优化工艺参数，并全面评估焊接/加工样品的微观结构变化和力学性能。 。因此，这篇综述文章旨在概述FSW / FSP铝合金在微观组织演变和力学性能方面的最新进展。特别注意重结晶机理，晶界特征，相变，织构演变，特征微观结构，