(上海航天設(shè)備制造總廠有限公司，上海 200245)
摘 要: 采用帶非圓截面攪拌針的焊接工具對5A06與2219鋁合金進(jìn)行了攪拌針下壓的回填式摩擦點焊試驗，對焊點進(jìn)行微觀組織結(jié)構(gòu)分析與力學(xué)性能測試。結(jié)果表明：在焊接過程中，特殊的材料流動使得上板與下板的材料在焊點內(nèi)部呈層狀混合，并在焊點中心下部形成了上板材料留存區(qū)域。焊點完全消除了傳統(tǒng)套筒下壓帶來的焊點豎直界面弱連接及環(huán)溝槽現(xiàn)象，但更容易在焊點下部形成延伸至焊核內(nèi)部的界面殘留，隨著下壓量的增加，進(jìn)一步演變?yōu)橄蛳掳鍙澢腍ook特征。拉剪試驗表明，焊點斷裂載荷隨下壓量增大而增加，最大拉剪力為5.7 kN；斷裂模式為由焊點底部Hook缺陷起裂，穿過焊核區(qū)擴展斷裂。
關(guān)鍵字: 回填式摩擦點焊；攪拌針下壓；異種鋁合金；顯微組織；力學(xué)性能
（Shanghai Aerospace Equipments Manufacture Co., Ltd., Shanghai 200245, China）
Abstract:5A06/2219 aluminum alloy was pin plunge refill friction spot welded using non-circular cross section pin, the microstructure and tensile property of the joint were discussed. The results show that the special materials flow in welding spot makes upper and lower plates materials mixed in a multi-layer structure, and forms a residual area of upper plate material. The welding spot eliminates the weak-bonding of vertical interface in traditional sleeve plunge refill friction spot welding, but causes upper plate material of original lap interface extending into interior of stir zone, and as the plunge depth increases, makes it a characteristic of Hook defects. The tensile-shear tests show that the fracturing load of welding spots increases with the increase of plunge depth and the maximum tensile shear is 5.7 kN. It can be concluded that the cracks start with Hook defects and propagate into stir zone.
Key words: refill friction spot welding; pin plunge; dissimilar aluminum alloys; microstructure; mechanical property
