7150高强铝合金自支撑搅拌摩擦焊接头成形与组织研究  

Formation and Microstructure of Self-supporting Friction Stir Welded Joint of 7150 High-Strength Aluminum Alloy

作　　者：刘立安[1] 陈思浩 赵耀邦[1] 孟祥晨[2] 黄永宪[2] LIU Li'an;CHEN Sihao;ZHAO Yaobang;MENG Xiangchen;HUANG Yongxian(Shanghai Aerospace Precision Machinery Institute,Shanghai 201600,China;State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]上海航天精密机械研究所,上海201600 [2]哈尔滨工业大学先进焊接与连接国家重点实验室,黑龙江哈尔滨150001

出　　处：《热加工工艺》2023年第7期135-138,共4页Hot Working Technology

基　　金：中国航天科技集团有限公司第八研究院产学研合作基金项目(SAST2020-108);黑龙江省博士后面上资助项目(LBHZ20055)。

摘　　要：为解决高强铝合金搅拌摩擦焊(friction stir welding,FSW)背部需刚性支撑的问题,设计了自支撑搅拌摩擦焊分体式焊具,由上轴肩、搅拌针和下支撑体组成。采用下支撑体的结构设计可以进行7150-T77511铝合金的无垫板支撑FSW,并消除了传统FSW背部的弱连接缺陷。通过焊接工艺参数优化,当转速为550 r/min,焊接速度为500 mm/min时,焊缝成形良好,无内部缺陷。焊缝横截面组织呈“哑铃”形,工件上下层分别受上轴肩和下支撑体作用产生上焊核区和下焊核区,这两个区域的晶粒尺寸相近,相比焊核区晶粒更细小。Aiming at the problem that friction stir welding(FSW)of high-strength aluminum alloys needs rigid back supporting,a self-supporting friction stir welding tool was designed,which contains upper shoulder,stir pin and lower shoulder.The application of lower shoulder structure can realize the FSW of 7150-T77511 Al alloy without the supporting of backing plates,and eliminate the weak bond defect of conventional FSW.By optimizing the welding process parameters,the joint with excellent formation is obtained at the rotating velocity of 550 r/min and welding speed of 500 mm/min.The cross section structure of the joint present a"dumbbell"shape.Due to the influence of upper and lower shoulders,the grain sizes of upper and lower welding nugget zones are almost the same,which is smaller than that of the welding nugget area.

关 键 词：高强铝合金 搅拌摩擦焊 接头成形 显微组织 

分 类 号：TG453.9[金属学及工艺—焊接]