工具形貌对微型搅拌摩擦焊塑性金属流动及焊缝力学性能的影响  

Effect of Tool Morphology on Plastic Metal Flow and Weld Mechanical Properties in Micro-friction Stir Welding

作　　者：张昌青[1,2] 谷怀壮 马东东 王栋[1,2] 刘恩荣 张鹏省 ZHANG Changqing;GU Huaizhuang;MA Dongdong;WANG Dong;LIU Enrong;ZHANG Pengsheng(State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metal,Lanzhou University of Technology,Lanzhou 730050,China;School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Northwest Nonferrous Metals Research Institute,Xi'an 710016,China)

机构地区：[1]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,甘肃兰州730050 [2]兰州理工大学材料科学与工程学院,甘肃兰州730050 [3]西北有色金属研究院,陕西西安710016

出　　处：《电焊机》2025年第3期40-47,共8页Electric Welding Machine

基　　金：国家自然科学基金(52261013)。

摘　　要：微型搅拌摩擦焊(Micro Friction Stir Welding,μFSW)焊接过程中,由于搅拌工具尺寸的急剧减小造成产热不足及塑性金属流动差,导致表面成形不良以及内部孔洞、隧道等缺陷,因此搅拌工具的轴肩增加螺线结构来增强塑性金属的流动性被广泛采用。轴肩形貌的内凹提供了塑性金属流动空间,而工具与材料接触面积的增加也可提高摩擦产热。鉴于此,设计了轴肩形貌三螺旋线形貌(Ⅰ型)与内凹加三螺旋线(Ⅱ型)的两种搅拌工具,对板厚为0.5 mm的7075-T6铝合金进行超薄板搅拌摩擦焊对比试验,通过对焊接过程中的温度、横向力以及轴向力电信号的采集、焊接接头微观金相组织的观察及力学性能的测试分析,Ⅱ型相比于Ⅰ型工具焊接过程的峰值温度高出6%、塑性金属的流动行为由水平流动转变为内敛向上的空间流动、接头力学性能的抗拉强度提高11%,屈服强度提高2%,断后延伸率提高19.2%。试验表明,轴肩形貌采用内凹加三螺旋线有助于增加焊接过程的产热、促进塑性金属的流动及提高接头的力学性能。In the process of Micro Friction Stir Welding(μFSW),the drastic reduction of the size of the stirring tool will cause insufficient heat generation and poor plastic metal flow,resulting in poor surface forming and internal defects such as holes and tunnels.Therefore,the shaft shoulder of mixing tools is widely used to increase the flow of plastic metal by adding spiral structure.The concave shape of the shaft shoulder provides a space for the flow of plastic metal,and the increase of the contact area between the tool and the material can also increase the friction heat production.In view of this,this paper designed two kinds of stirring tools with three-helix shape of shaft shoulder(type I)and concave three-helix(typeⅡ),and conducted a comparative experiment of ultra-thin plate friction stir welding on 7075-T6 aluminum alloy with a plate thickness of 0.5mm.The collection of temperature,transverse force and axial force electrical signals in the welding process,the observation of the microscopic microstructure of the welded joint and the testing and analysis of mechanical properties show that the peak temperature of the welding process of the typeⅡtool is 6%higher than that of the type I tool,the flow behavior of the plastic metal changes from horizontal flow to internal and upward spatial flow,and the tensile strength of the mechanical properties of the joint is increased by 11%.The yield strength is increased by 2%,and the elongation after fracture is increased by 19.2%.The results show that the concave and triple helix shape of the shaft shoulder is helpful to increase the heat production,promote the flow of plastic metal and improve the mechanical properties of the joint.

关 键 词：微型搅拌摩擦焊 超薄板 工具形貌 内凹结构 三螺线结构 

分 类 号：TG453.9[金属学及工艺—焊接]