A critical assessment of various solid-state-bonding mechanisms is established for friction stir welding (FSW) processes of engineering alloys. The commonly assumed sintering-like diffusional-bonding hypothesis is criticized in this work as not the dominant mechanism. For the wide spectrum of material constitutive laws and FSW processing conditions examined and employed in realistic applications, the thermomechanical history on the workpiece–workpiece interface traverses in the creep-dominated regime for the growth/shrinkage of interfacial cavities. The evolution of the bonding fraction relies mainly on the creep strain rate in the adjourning workpieces, weakly on stress triaxiality, and negligibly on interfacial diffusion.

对工程合金的摩擦搅拌焊接（FSW）工艺建立了各种固态结合机制的关键评估。在这项工作中，通常假定的类似烧结的扩散键假设不是主要的机理。对于在实际应用中检查和采用的各种材料本构定律和FSW处理条件，工件-工件界面上的热机械历史以蠕变为主的状态遍历，以增大/减小界面腔。结合分数的变化主要取决于在延展的工件中的蠕变应变率，而对应力三轴性的依赖较小，而对界面扩散的影响则微不足道。