异种铝合金摩擦塞补焊接头微观组织及性能

Microstructure and Mechanical Properties of Friction Plug Welding Joints for Dissimilar Aluminum Alloys

采用2A14-T6铝合金圆锥塞棒和10 mm厚2219-T87铝合金板材进行异种铝合金摩擦圆锥塞焊工艺试验。对异种铝合金摩擦锥塞焊接头的缺陷特征、微观组织、强化相分布、力学性能及拉伸断口形貌进行观察与测试。结果表明:在焊接转速为7 500 r/min,焊接压力为30 k N和35 k N时得到了无缺陷的摩擦塞焊接头;摩擦塞焊接头可分为塞棒区(Plug metal,PM)、塞棒焊缝热力影响区(Plug thermo-mechanically affected zone,PTMAZ)、摩擦界面区(Friction interface zone,FIZ)、热力影响区(Thermo-mechanically affected zone,TMAZ)、热影响区(Heat affected zone,HAZ)和母材区(Base metal,BM)六部分;硬度测试结果显示,母材区硬度最高,塞棒区和塞棒焊缝热力影响区硬度略低于母材,热力影响区和热影响区最低。摩擦塞焊接头的抗拉强度最高可达312 MPa,伸长率可达4.1%;接头在下表面HAZ与TMAZ的交界处起裂,自下表面向上表面扩展,经过TMAZ,最终在上表面的PTMAZ断裂,断口呈韧窝形貌。

In this paper, friction plug welding（FPW） process of 10 mm thick 2219-T87 aluminum alloy with 2A14-T6 aluminum plug are performed. The defect characteristics, microstructures and phase distribution, mechanical properties, fracture morphology of FPW joints are observed and tested respectively. The results show： Defect-free FPW joints are obtained with a 30 kN or 35 kN welding pressure and a 7 500 r/min rotational speed; The FPW joint can be divided into six parts, plug metal（PM）, plug thermo-mechanically affected zone （PTMAZ）, recrystallized zone （RZ）, thermo-meehanically affected zone（TMAZ）, heat affected zone （HAZ） and base metal（BM）; Hardness test results indicate that the highest hardness locates in base metal, followed by the plug zone and plug thermo-mechanically affected zone, with the lowest hardness occurred in thermo-mechanically affected zone and heat affected zone; The tensile strength and elongation of FPW joints can reach to 312 MPa and 4.1%, respectively; The initial fracture locates at the interface of TMAZ and HAZ on the bottom surface, finally fractures at PTMAZ, exhibiting＇ dimple morphology.