Si元素对钛/钢异种金属接头成形及微观组织影响  

Effects of Si element on the weld formation and microstructure of titanium/steel dissimilar joints

作　　者：孙清洁[1,2] 陶玉洁 甄祖阳 刘一搏 张清华[1,2] 刘岳 SUN Qingjie;TAO Yujie;ZHEN Zuyang;LIU Yibo;ZHANG Qinghua;LIU Yue(State Key Laboratory of Precision Welding&Joining of Materials and Structures,Harbin Institute of Technology,Harbin,150001,China;Shandong Provincial Key Laboratory of Special Welding Technology,Harbin Institute of Technology at Weihai,Weihai,264209,China)

机构地区：[1]哈尔滨工业大学,材料结构精密焊接与连接全国重点实验室,哈尔滨150001 [2]哈尔滨工业大学(威海),特种焊接技术省重点实验室,威海264209

出　　处：《焊接学报》2025年第1期1-7,共7页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(52275320、52175299)。

摘　　要：采用T2Cu和CuSi3焊丝在相同工艺参数下对厚度为1 mm的TC4钛合金及304不锈钢进行焊接,并借助光学显微镜(optical microscopy,OM)和扫描电镜(scanning electron microscopy,SEM)研究了两种焊丝下的TC4/304异种金属焊接熔池冶金行为.对比分析了不同焊丝成分,尤其是Si元素的加入对TC4/304异种金属接头宏观成形、界面微观组织和力学性能的影响.结果表明,Si元素的加入使液态熔池流动性显著增强,消除了凹陷和孔洞等缺陷,解决了焊缝背部熔合不良问题,焊缝宏观成形显著改善.两种焊丝均有效阻隔了Ti,Fe原子,钛/铜界面未生成Ti-Fe化合物,但在焊缝中心以及铜/钢界面处生成了少量Ti-Fe相.CuSi3焊丝中充足的Si元素不仅使Ti5Si3相形核生长的更加充分,在熔池流动的作用下均匀分布于焊缝中,对接头起到弥散强化作用.与T2Cu焊丝相比,CuSi3焊丝所得接头的抗拉强度提升了81.4%,最高达到366.8 MPa.Welding of 1mm thick TC4 titanium alloy and 304 stainless steel was performed using T2Cu and CuSi3 welding wires under the same process parameters.The metallurgical behavior of the TC4/304 dissimilar metal weld pool was studied using optical microscopy(OM)and scanning electron microscopy(SEM).A comparative analysis was conducted on the effects of different wire compositions,particularly the addition of silicon(Si),on the macro formation of the TC4/304 dissimilar metal joints,the microstructure at the interface,and the mechanical properties.The results showed that the addition of Si significantly enhanced the fluidity of the liquid weld pool,eliminated defects such as depressions and pores,and addressed issues of poor fusion at the back of the weld,leading to substantial improvements in macro formation of the welds.Both types of welding wires effectively hindered the diffusion of Ti and Fe atoms,preventing the formation of Ti-Fe compounds at the Ti/Cu interface,although a small amount of Ti-Fe phase was present at the center of the weld and at the Cu/Fe interface.The sufficient Si content in CuSi3 welding wire not only promoted more effective nucleation and growth of the Ti5Si3 phase but also allowed for its uniform distribution throughout the weld due to the flow of the weld pool,providing a dispersion strengthening effect for the joint.Compared to T2Cu welding wire,the joints obtained with CuSi3 welding wire exhibited a tensile strength increase of 81.4%,reaching a maximum of 366.8 MPa.

关 键 词：钛/钢异种金属焊接 SI元素 焊缝成形 微观结构 弥散强化 

分 类 号：TG442[金属学及工艺—焊接]