Ti/Al异种合金电弧熔钎焊接头界面断裂行为分析  

Analysis of interface fracture behavior of arc fusion-brazed joint between titanium and aluminum dissimilar alloys

作　　者：吕世雄[1] 崔庆龙[1] 黄永宪[1] 敬小军 

机构地区：[1]哈尔滨工业大学先进焊接与连接国家重点实验室,哈尔滨150001 [2]成都四威高科技产业园有限公司,成都611731

出　　处：《焊接学报》2013年第6期33-36,114-115,共4页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(50974046;50904020);哈尔滨市青年科技创新人才基金资助项目(2009RFQXG050);中央高校基础科研业务费专项资金资助项目(HIT.NSRIF.2012007);国家博士后科学基金资助项目(20090460883;201003419)

摘　　要：采用TIG电弧的方法实现了钛合金与铝合金熔钎焊连接,分析了不同焊丝形成的熔钎焊接头的界面组织和断裂特征.结果表明,纯铝接头界面为单一的TiAl3相,裂纹主要沿着TiAl3反应层与焊缝之间的界面扩展.拉伸时首先从坡口拐角启裂,当裂纹扩展至接头反面时,断裂扩展形式转变为从焊缝金属撕裂,接头抗拉强度为139MPa.添加Al-Cu-La焊丝的接头界面结构为TiAl3+Ti2Al20La双化合物层,拉伸时沿TiAl3反应层与钛合金界面开裂,以界面内的微裂纹为裂纹源并向反应层内扩展,属于准解理断裂,接头抗拉强度达270 MPa.稀土La元素作用下形成的双化合物层是提高接头强度的关键.Fusion-brazing of titanium alloy to aluminum alloy was achieved by TIG arc,and the interface microstructure and fracture characteristics of the joints made with different fillers were analyzed.The results indicate that the interface microstructure in the joints with pure Al filler consisted of TiAl3 phase,and cracks initiated at the interface corner and propagated along the interface between TiAl3 layer and welded seam.The facture style changed to tearing through the welded seam when the crack propagated to the back side,and the tensile strength of the joint was 139 MPa.In contrast,the interface of the joints with Al-Cu-La filler exhibited dual layers,containing TiAl3 and Ti2Al20La phases.The fracture happened along the interface between TiAl3 layer and Ti alloy substrate.The microcracks at the interface acted as the crack sources during the tensile test,and the fracture occurred in the interfacial layer with quasi-cleavage features.The tensile strength of joint with Al-Cu-La filler reached 270 MPa.The double compound layers formed due to the effect of La,which was the key to improve the joint strength.

关 键 词：Ti/Al异种合金 电弧熔钎焊 界面反应层 断裂行为 

分 类 号：TG454[金属学及工艺—焊接]