塞棒材料对铝合金摩擦塞补焊接头组织及拉伸断裂行为的影响

Effect of Plug Materials on Microstructure and Tensile Fracture Behavior of Aluminum Alloy Friction Plug Welds

分别采用2A14-T6和2219-T87铝合金塞棒对6mm厚2219-T87铝合金板进行摩擦塞补焊实验,利用数字图像相关方法观测塞棒材料对拉伸过程中接头变形及断裂行为的影响,同时对两种接头的微观组织、显微硬度及拉伸断口进行观察与测试。结果表明:两种接头的组织特征相似,但2A14-T6接头的塞棒热力影响区发生部分再结晶的区域比2219-T87接头宽;塞棒材料对接头抗拉强度影响不大,但对伸长率影响显著,2219-T87接头抗拉强度可达346.2MPa,伸长率为5.76%;2A14-T6接头的抗拉强度可达351.2MPa,伸长率为3.54%;2219-T87接头的变形主要集中在软化的塞棒区和塞棒热力影响区,而2A14-T6接头的变形主要集中在软化的热力影响区和热影响区;再结晶区和接头软化区是整个接头的薄弱区,拉伸断口呈韧窝形貌。

Friction plug welding （FPW） experiments were performed on 6mm 2219-T87 aluminium alloy using 2219-T87 and 2A14-T6 plugs. Digital image correlation method was used to determine the deformation and fracture behaviour of FPW joints in tensile process,meanwhile the microstructure, microhardness, and tensile fracture surface of the two FPW joints were observed and tested respectively. The results show that the two joints present similar microstructure, while 2A14-T6 joint exhibits wider partial recrystallized zone in plug thermo-mechanically affected zone than 2219-T87 joint. The plug material has slight effect on ultimate tensile strength, but has a significant effect on the elongation . The tensile strength and elongation of 2219-T87 joint can reach 346.2MPa and 5.76%, for 2A14-T6 joint, they are 351.2MPa, 3.54%. The deformation mainly concentrates in softening plug thermo-mechanically affected zone and plug metal for 2219-T87 joint, while the deformation concentrates in softening thermo-mechanically affected zone and heat affected zone for 2A14-T6 joint. Recrystallized zone and the softening zone are the weakening zones across the whole joint, and the tensile fracture morphologies are characterized by dimples.