(1. 南京航空航天大學 材料科學與技術學院，南京 210016；
2. 中國航天科工集團 南京晨光廠 工藝研究所，南京210012)
摘 要: 采用伸縮式攪拌頭對25 mm板厚2219-T6鋁合金進行攪拌摩擦焊，在多道補焊時避免攪拌頭軸肩的二次下壓量造成的底部焊穿。對25 mm板厚2219-T6攪拌摩擦焊焊縫的微觀組織、材料缺失型缺陷及弱連接型缺陷進行觀察。結果表明：焊縫沿厚度方向分為軸肩影響區(qū)和攪拌針影響區(qū)，焊接參數(shù)的變化與這兩區(qū)域中缺陷的產(chǎn)生存在一定關系，焊縫中的材料缺失型缺陷遵循一定的體積守恒關系。利用伸縮式攪拌頭制備不同尺寸的焊縫根部未焊透缺陷，發(fā)現(xiàn)未焊透的深度與焊縫抗拉強度呈非線性關系。在統(tǒng)一的焊接參數(shù)規(guī)范下，調(diào)整攪拌針伸出長度進行多道焊，研究多道補焊工藝對焊縫組織性能的影響。
關鍵字: 2219鋁合金；攪拌摩擦焊；焊縫缺陷；伸縮式攪拌頭；多道焊
thick aluminum plates with telescopic stir-pin
（1. College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics,
Nanjing 210016, China;
2. Technology Research Institute of Nanjing Chenguang Corporation,
China Aerospace Science and Technology Corporation, Nanjing 210012, China）
Abstract:By using the telescopic stir-pin, 25 mm-thickness 2219-T6 aluminum alloy couple plates were successfully friction-stir welded, and no plunge-through defect induced by the press amount of tool-shoulder was observed in the multi-pass repairing welding process. The microstructures in sound friction-stir welds, material-loss typed and weak-link typed weld defects were observed. The results show that the weld along the weld-thickness direction can be divided into shoulder-affected and pin-affected zones. The formation of defects is associated with the change of the welding parameters, and the inner material-loss typed defects follow volume conservation relationship. For the welds with different-size root flaws prepared by telescopic stir-pin, a non-linear relationship exists between the root-flaw depth and the weld tensile strength. In addition, under the unified welding parameters, by adjusting the telescopic pin length, the effects of multi-pass welding on the microstructure and properties of the resultant welds were investigated.
Key words: 2219 aluminum alloy; friction stir welding; weld defect; telescopic stir-pin; multi-pass welding
