New Technique to Repair Keyhole of 2195 Al-Li Alloy Friction Stir Welding Joints

• Published in: Materials Vol. 17; no. 14; p. 3418
• Main Authors: Meng, Xiangchen, Chen, Xi, Han, Zhulin, Yuan, Jingyu, Xie, Yuming, Dong, Jihong, Xia, Peiyun, Huang, Yongxian
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.07.2024
• Subjects: 2195 Al-Li alloy; Alloys; Aluminum-lithium alloys; Bonded joints; Bonding strength; Comparative analysis; Crystal defects; Ductile fracture; Ductile-brittle transition; Dynamic recrystallization; Fractures (Geology); Friction stir processing; Friction stir welding; Gas tungsten arc welding; Gas welding; Hardness; Inert gas welding; keyhole; Keyholes; Maintenance and repair; Mechanical properties; Methods; Microhardness; Microstructure; Morphology; Rare gases; Tensile strength; tungsten inert gas welding; Welded joints; Welding; China; Japan
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17143418

Aiming at the repairing of keyhole defects after friction stir welding of complex structures, a new method combined with tungsten inert gas welding (TIG) and friction stir processing (FSP) was proposed. The results showed that the pre-filling wire of TIG can completely fill the volumetric keyhole. FSP can refine the coarse grain area into equiaxial grains due to dynamic recrystallization, while some pore defects are eliminated. The interface bonding quality is high. The microhardness of the repairing zone with FSP is significantly stronger than that of the untreated parts. Compared to direct TIG repairing, the introduction of FSP transformed the fracture from brittle fracture to ductile fracture, and the tensile strength of the joint was increased by 131.7%, realizing the high-quality repairing of keyhole defects in 2195 Al-Li alloy.