(天津大學(xué) 天津市現(xiàn)代連接技術(shù)重點(diǎn)實(shí)驗(yàn)室，天津 300072)
摘 要: 采用攪拌摩擦焊方法成功獲得3種不同組合形式(搭接/對搭接/對接)的6061-T4鋁合金T型接頭。對接頭的焊接缺陷、微觀組織、硬度分布及抗拉強(qiáng)度分別進(jìn)行觀察和測試。結(jié)果表明：在前進(jìn)側(cè)圓角過渡區(qū)或筋板焊核區(qū)，3種接頭均容易出現(xiàn)隧道缺陷；弱結(jié)合缺陷由于塑性變形偏離原始連接界面而向筋板或者壁板前進(jìn)側(cè)偏移；與常規(guī)攪拌摩擦焊對接搭接接頭不同，T型接頭沿筋板方向出現(xiàn)熱機(jī)影響區(qū)和兩個(gè)圓角過渡區(qū)；軟化區(qū)域和弱結(jié)合是導(dǎo)致沿壁板拉伸強(qiáng)度降低的主要原因，而弱結(jié)合和隧道缺陷是引起這3種T型接頭沿筋板方向斷裂的重要原因。
關(guān)鍵字: 6061鋁合金；攪拌摩擦焊；T型接頭；組合形式；焊接缺陷
（Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin 300072, China）
Abstract:Three combination modes (T-lap/T-butt-lap/T-butt) of AA6061-T4 aluminum alloy T-joints were successfully jointed by friction stir welding. Welding defects, microstructure, hardness profiles and tensile strength of the obtained T-joints were observed and measured, respectively. The results show that tunnel defects are easily formed in the fillet zone of the advancing side or in stringer nugget zone for all the three modes of T-joints. Defects of kissing bond are extruded downward to the stringer or sideward from the original joining surfaces to the advancing side of the skin under severe plastic deformation. T-joints exhibit the thermo-mechanical affected zone and two fillet zones in the stringer, which are different from the conventional butt and lap joints of friction stir welding. Softening zones and kissing bond are the main reasons to reduce the tensile strength of T-joints along skin direction, and kissing bond and tunnel defects are the main reasons for the fractures of T-joints along stringer direction.
Key words: 6061 aluminum alloy; friction stir welding; T-joints; combination mode; welding defect
