Friction stir welding (FSW) process is currently considered as a promising alternative to join aluminium alloys. Indeed, this solid-state welding technique is particularly recommended for the assembly of these materials. Since parts are not heated above their melting temperature, FSW process may prevent solidification defects encountered in joining aluminium alloys and known as limitations to the dissemination of these materials in industries. During the past years, large literature has been devoted to the modelling of microstructural evolution in aluminium alloys during FSW processes and mainly dedicated to the analysis of precipitate evolutions and grain recrystallization mechanisms. Precipitate size distribution models have aroused widespread interest in recent years demonstrating their relevance to follow precipitation process in multicomponent alloys and multiphase systems. Efficient recrystallization models are also available and based on various grain growth mechanisms. In addition, multi-scale coupling strategies have recently emerged considering thermal, mechanical and metallurgical solutions. Consequently, the effect of FSW process parameters on weld properties is now investigated to determine optimized welding strategies regarding microstructure evolution. This research is based on reliable models reported in the literature enhancing the estimation of final weld state and associated properties as an answer to industrial needs. Validations of proposed modelling strategies have been reported based on in-depth analyses of experimental observations. This present work proposes a review of recent models dedicated to microstructural evolutions in aluminium alloys during FSW process. The interest and efficiency of current approaches will be discussed to highlight their limitations. Guidelines will propose new routes toward enhanced modelling strategies for future developments.

中文翻译：

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铝合金 FSW 过程中发生的微观结构变化及其建模综述

搅拌摩擦焊 (FSW) 工艺目前被认为是连接铝合金的一种有前途的替代方法。事实上，这种固态焊接技术特别推荐用于组装这些材料。由于零件不会加热到高于其熔化温度，FSW 工艺可以防止在连接铝合金时遇到凝固缺陷，这也被称为限制这些材料在工业中的传播。在过去的几年中，大量文献致力于模拟 FSW 过程中铝合金的显微组织演变，主要致力于分析析出物演变和晶粒再结晶机制。近年来，沉淀尺寸分布模型引起了广泛的兴趣，证明了它们与跟踪多组分合金和多相系统中的沉淀过程的相关性。还可以使用基于各种晶粒生长机制的有效再结晶模型。此外，最近出现了考虑热、机械和冶金解决方案的多尺度耦合策略。因此，现在研究 FSW 工艺参数对焊接性能的影响，以确定有关微观结构演变的优化焊接策略。这项研究基于文献中报道的可靠模型，增强了对最终焊接状态和相关属性的估计，作为对工业需求的回答。已根据对实验观察的深入分析报告了对拟议建模策略的验证。目前的工作提出了对最近专门用于 FSW 过程中铝合金显微结构演变的模型的回顾。将讨论当前方法的兴趣和效率，以突出它们的局限性。指南将为未来的发展提出增强建模策略的新途径。