6082铝合金摩擦塞补焊接头微观组织与性能  

Microstructure and Mechanical Properties of Friction Plug Welding Joint of 6082 Aluminum Alloy

作　　者：张忠科[1,2] 赵早龙 李德福 郑江辉 ZHANG Zhongke;ZHAO Zaolong;LI Defu;ZHENG Jianghui(School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China;State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学材料科学与工程学院,兰州730050 [2]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050

出　　处：《材料导报》2020年第16期16094-16099,16113,共7页Materials Reports

基　　金：航空科学基金(201611U2001);甘肃省科技重大专项(18ZD2GC013)。

摘　　要：在不同的焊接转速下,对5 mm厚的6082铝合金进行顶锻式摩擦塞补焊实验研究,分析了塞补焊接头的金属流动性、微观组织、第二相分布、温度场、力学性能、显微硬度以及断口形貌特征。结果表明:塞补焊接头截面上层金属流动性明显优于下层;焊缝根部受摩擦热最低且金属流动性差,使其成为整个塞补焊接头的薄弱区;在摩擦界面区,塞棒大量细密的等轴晶穿插进母材板条状的晶粒中,实现了塞补焊接头的紧密连接;焊接接头不同区域β(Mg 2Si)相的大小、数量及方向均有不同程度的变化;在焊接转速2200 r/min下,焊接接头力学性能最好,接头抗拉强度达到母材的75%以上,断后伸长率达到了母材的64%以上;焊接接头断裂在塞孔与塞棒之间的摩擦界面区,裂纹从焊缝根部弱连接区域起裂并向焊缝表面扩展,断裂方式为韧性断裂;整个塞补焊接头母材侧热机影响区和热影响区结合处软化最为严重,硬度值在(60±5)HV之间。In this work,friction plug welding(FPW)process of 5 mm thick 6082-T8 aluminium alloy with 6082-T6 plug aluminium was performed at diffe-rent welding speeds.The metal fluidity,microstructure,second phase distribution,temperature field,mechanical properties,hardness and fracture morphology of FPW joint were analyzed and tested respectively.The results show:the upper half of FPW joint section has good metal flui-dity;the lowest friction heat at the root of the weld makes it the weak zone of FPW joint;in the friction interface zone(FIZ)of FPW joint,a large number of fine equiaxed grains in plug mental(PM)penetrate into the strip grains of base metal(BM)tightly,thus realizing the close bonding of FPW joint;the size,quantity and direction ofβ(Mg 2Si)phase in different areas of welded joints have different changes;the FPW joint has the best welding mechanical properties at the welding speed of 2200 r/min,the tensile strength and elongation of the joint reach more than 75%and 64%of BM,respectively;at the fracture position of the joint in the FIZ,the crack extends from the weak joint zone at the root of the weld to the surface of the weld,showing ductile fracture;hardness test results indicate that the lowest hardness occurred in base thermo-mechanically affec-ted zone and heat affected zone.

关 键 词：6082铝合金 摩擦塞补焊(FPW) 微观组织 力学性能 

分 类 号：TG456[金属学及工艺—焊接]