TIG补焊对2219铝合金搅拌摩擦焊接接头微观组织及性能影响  

Effect of TIG Repair Welding on Microstructure and Properties of Friction Stir Welding Joint of 2219 Aluminum Alloy

作　　者：刘育宁 张健 刘德博 王非凡 周利[1,2] LIU Yuning;ZHANG Jian;LIU Debo;WANG Feifan;ZHOU Li(State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001;Shandong Provincial Key Laboratory of Special Welding Technology,Harbin Institute of Technology at Weihai,Weihai 264209;Beijing Institute of Astronautical Systems Engineering,Beijing 100076)

机构地区：[1]哈尔滨工业大学,先进焊接与连接国家重点实验室,哈尔滨150001 [2]哈尔滨工业大学(威海),山东省特种焊接技术重点实验室,威海264209 [3]北京宇航系统工程研究所,北京100076

出　　处：《宇航材料工艺》2022年第6期77-82,共6页Aerospace Materials & Technology

基　　金：北京宇航系统工程研究所课题支持(DQ19009)。

摘　　要：通过对原始搅拌摩擦焊(FSW)接头中间位置进行缺口挖补以模拟焊缝缺陷,采用钨极氩弧焊(TIG)补焊对其进行焊缝缺陷修复试验,研究该补焊工艺对接头微观组织及力学性能的影响规律,为贮箱的FSW焊缝性能评价提供技术支撑和后续工程指导。结果表明,相较于FSW接头,补焊接头TIG焊缝区主要由较大的等轴树枝晶组成,且与FSW焊缝交界处相互掺杂着粗大等轴晶和细小等轴晶;补焊接头固溶区受热循环影响较大,晶粒较为粗大,而过时效区受热循环影响较小,会发生过时效化并形成软化区。补焊接头抗拉强度与延伸率相较于原始FSW接头有所降低,硬度分布大致呈“W”形,WNZ区为硬度值最低处;补焊接头断裂位置始于焊趾处,断口存在大量韧窝,同时韧窝内存在第二相粒子,呈现韧性断裂机制。The notch in the middle of the original friction stir welding(FSW)joint was patched to simulate the weld defects.The weld defects in the middle position of the FSW joint were repaired by Tungsten Inert Gas(TIG).The influence of the repair welding process on the microstructure and mechanical properties of the joint was studied to provide technical support and follow-up engineering guidance for the performance evaluation of the FSW weld of the tank.The results show that the TIG weld zone of the repaired joint is mainly composed of coarse equiaxed dendrites as compared to FSW joint.At the interface between the FSW joint and repaired joint coarse equiaxed grains and refined equiaxed grains are intermingled.The solid-solution zone of the repaired joint is greatly affected by the thermal cycle with coarsened grain,while the overaging zone is less affected by the thermal cycle with the occurance of over-aging phenomenon and the presence of a softening zone.The tensile strength and elongation of the repaired joint are decreased as compared to the original FSW joint.The hardness distribution is substantially"W"shape with the lowest hardness in the WNZ.Crack initiation of the repaired joint occurs at the weld toe displaying a large number of dimples on the fracture surface.Meanwhile,second phase particles are detected in the dimples showing a typical ductile fracture mechanism.

关 键 词：2219铝合金 搅拌摩擦焊 钨极氩弧焊补焊 显微组织 力学性能 

分 类 号：TG457.[金属学及工艺—焊接]