由常规搅拌摩擦焊演变而来的摩擦塞焊、填充搅拌摩擦焊与主被动填充搅拌摩擦焊等工艺可用于金属结构中体积型缺陷修复，但添加材料与母材间的界面常出现由固态焊合不良而造成的弱连接或孔洞缺陷，严重制约了修复工艺的工程应用。本项目提出利用搅拌与超声耦合作用可实现超扩散的思想来提高连接界面的固态焊合效果，并以超声辅助径向增材搅拌摩擦焊（UA-RAFSW）新工艺为例开展研究。基于优化的搅拌与振动一体化工具系统，研究超声的加入对焊接过程中的材料热力学行为、应变速率、原子扩散行为与修复区断裂行为的影响，建立超声与搅拌耦合下的原子超扩散物理模型，揭示UA-RAFSW的焊接机理，明晰UA-RAFSW工艺实现基于同质材料修补超差孔的可行性。本项目提出的新工艺不仅可进行管管套接与超差孔修复等问题，而且研究成果还将推动包括常规FSW在内的固相焊技术的焊接机理研究，具有重要的科学意义与实际工程意义。

As variants of traditional friction stir welding (FSW), friction plug welding, filling FSW and active-passive filling FSW can be applied to repair the volume defect in metal structures. However, due to weak solid state bonding, kissing bond and even cavity defect always occur at the joining interface between extra-added material and base metal, seriously restricting the practical engineering application of these above-mentioned repairing technologies. The project is based on that the combined effect of stir and ultrasonic can realize the atom super diffusion and then heighten solid state bonding at the joining interface. Ultrasonic aided radial additive FSW (UA-RAFSW) is put forward. On basis of the optimized stir-vibration tool system, thermo-mechanics behavior, strain rate, microstructure and atom diffusion behavior during the welding process and fracture mechanism of repaired region are investigated under the addition of ultrasonic. The atom super diffusion model under the combined effect of stir and ultrasonic is established and the welding mechanism of UA-RAFSW is presented. Whether UA-RAFSW process can be applied to repair the hole using similar material is discussed. The UA-RAFSW process in the project can not only realize to repair the hole with exceeded tolerance, but also accelerate mechanism investigation of solid state welding technologies including traditional FSW. The project owns important scientific significance and practical engineering value.