摘要
提出根据搅拌摩擦焊的低温和大塑性变形特性,采用仅将搅拌头在上板铝合金中进行搅拌,并将镀锌钢表面的镀锌层作为中间层材料,以提高铝合金与钢的界面冶金结合及其疲劳性能。结果表明,利用搅拌摩擦焊的热力耦合作用,通过镀锌层极大地提高了铝合金与钢的焊接性。具有钎料作用的镀锌层阻止了铝和钢的直接接触,从而避免了金属间化合物的生成,锌在铝/钢界面的返回侧较为聚集,而在其前进侧形成了典型的铝-锌固溶体组织。焊缝中心的锌被挤出,在界面处发现了热镀过程中形成的纳米尺度的Fe_(3)Al和Fe_(4)Al_(13)。铝/钢搅拌摩擦钎焊接头剪切强度较为稳定,其最大剪切强度和延伸率分别可达333.8N/mm和11.33%。在疲劳载荷的作用下,铝/钢搅拌摩擦钎焊接头的失效模式有三种:较高应力水平下的铝/钢界面断裂、中等应力水平下的混合断裂及较低应力水平下的母材断裂和界面断裂。在疲劳应力水平为2.64 kN时,接头循环2×10^(6)次而未发生断裂。
Based on character of friction stir welding such as low temperature and severe plastic deformation,the tool only stir in the top Al alloy,which promotes thermodynamic couple,coupling with the interlayer of zinc coating on the steels to improve interfacial bonding and fatigue performance of Al/steel dissimilar welds.The investigation indicated that making use of thermodynamic couple mechanism,the zinc coating improved weldability of Al alloy and steel.As a brazing filler metal,the zinc coating layer avoides direct contact between Al alloy and steel,and thus avoides the formation of intermetallic compound.The zinc material gathered around the retreating side on the Al/steel interface,and typical eutectic structure of Al and Zn are formed on the advancing side at the Al/steel interface.The zinc material is squeezed outside of the stirring zone,where nano scaled Fe_(3)Al Fe_(4)Al_(13)are identified,which are formed during the hot-dipping process.Lap shear strength of the friction stir brazed Al/steel dissimilar welds are stable,the maximum lap shear strength and elongation reached 333.8 N/mm and 11.33%,respectively.Under the fatigue load,three different failure modes are observed:interfacial failure under higher load,mixed failure under medium load,base metal failure and interfacial failure under lower load.The cycle can reach 2×10^(6)without failure under a load of 2.64 kN.
作者
申志康
王波
杨益
管月辉
周平
侯文涛
朴钟宇
刘小超
黄国强
杨夏炜
陈海燕
田艳红
李文亚
李会军
SHEN Zhikang;WANG Bo;YANG Yi;GUAN Yuehui;ZHOU Ping;HOU Wentao;PIAO Zhongyu;LIU Xiaochao;HUANG Guoqiang;YANG Xiawei;CHEN Haiyan;TIAN Yanhong;LI Wenya;LI Huijun(College of Engineering and Technology,Southwest University,Chongqing 400715;State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin 150001;School of Mechanical,Materials and Mechatronic Engineering,University of Wollongong,Wollongong NSW 2522,Australia;College of Mechanical Engineering,Zhejiang University of Technology,Hangzhou 310023;School of Mechanical Engineering,Southeast University,Nanjing 211189;College of Materials Science and Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 210016;Shaanxi Key Laboratory of Friction Welding Technologies,Northwestern Polytechnical University,Xi'an 710072)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2024年第22期130-138,共9页
Journal of Mechanical Engineering
基金
国家自然科学基金(52174374,U23A20622,51975479)
先进焊接与连接国家重点实验室开放课题(AWJ-23M15)
中央高校基本科研业务费专项资金(SWU-KR22034)资助项目。
关键词
搅拌摩擦钎焊
铝合金
镀锌钢
连接机理
疲劳性能
friction stir brazing
Al alloys
zinc coated steels
interfacial bonding mechanism
fatigue performance
