Effect of brazing temperature on microstructure and tensile strength ofγ-TiAl joint vacuum brazed with micro-nano Ti−Cu−Ni−Nb−Al−Hf filler  

钎焊温度对微纳米Ti−Cu−Ni−Nb−Al−Hf钎料真空钎焊γ-TiAl接头组织和抗拉强度的影响

作　　者：Li LI Yu-tong CHEN Lei-xin YUAN Fen LUO Zhi-xue FENG Xiao-qiang LI 李力;陈昱橦;袁雷昕;罗芬;冯志雪;李小强(华东交通大学材料科学与工程学院,南昌330013;华东交通大学轨道交通基础设施性能监测与防护国家重点实验室,南昌330013;华南理工大学国家金属材料近净成形工程技术研究中心,广州510640)

机构地区：[1]School of Materials Science and Engineering,East China Jiaotong University,Nanchang 330013,China [2]State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure,East China Jiaotong University,Nanchang 330013,China [3]National Engineering Research Center of Near-net-shape Forming for Metallic Materials,South China University of Technology,Guangzhou 510640,China

出　　处：《Transactions of Nonferrous Metals Society of China》2024年第8期2563-2574,共12页中国有色金属学报（英文版）

基　　金：the National Natural Science Foundation of China(No.51865012);the Natural Science Foundation of Jiangxi Province,China(No.20202BABL204040);the Open Foundation of National Engineering Research Center of Near-net-shape Forming for Metallic Materials,China(No.2016005);the Science Foundation of Educational Department of Jiangxi Province,China(No.GJJ170372);the GF Basic Scientific Research Project,China(No.JCKY2020205C002);the Civil Population Supporting Planning and Development Project,China(No.JPPT125GH038).

摘　　要：A novel micro-nano Ti−10Cu−10Ni−8Al−8Nb−4Zr−1.5Hf filler was used to vacuum braze Ti−47Al−2Nb−2Cr−0.15B alloy at 1160−1220℃ for 30 min.The interfacial microstructure and formation mechanism of TiAl joints and the relationships among brazing temperature,interfacial microstructure and joint strength were emphatically investigated.Results show that the TiAl joints brazed at 1160 and 1180℃ possess three interfacial layers and mainly consist of α_(2)-Ti_(3)Al,τ_(3)-Al_(3)NiTi_(2) and Ti_(2)Ni,but the brazing seams are no longer layered and Ti_(2)Ni is completely replaced by the uniformly distributed τ_(3)-Al_(3)NiTi_(2) at 1200 and 1220℃ due to the destruction of α_(2)-Ti_(3)Al barrier layer.This transformation at 1200℃ obviously improves the tensile strength of the joint and obtains a maximum of 343 MPa.Notably,the outward diffusion of Al atoms from the dissolution of TiAl substrate dominates the microstructure evolution and tensile strength of the TiAl joint at different brazing temperatures.采用自主研制的新型Ti−10Cu−10Ni−8Al−8Nb−4Zr−1.5Hf微纳米钎料,在钎焊温度1160~1220℃、钎焊时间30 min的工艺参数下真空钎焊连接Ti−47Al−2Nb−2Cr−0.15B合金。研究TiAl钎焊接头的界面组织和形成机理,以及钎焊温度、界面组织和接头强度之间的内在联系。结果表明,钎焊温度1160和1180℃的TiAl接头均由三个界面反应层组成,主要物相均为α_(2)-Ti_(3)Al、τ_(3)-Al_(3)NiTi_(2)和Ti_(2)Ni。然而,当钎焊温度为1200和1220℃时,由于具有壁垒效应的连续α_(2)-Ti_(3)Al层被打破,导致钎缝中未见明显分层,τ_(3)-Al_(3)NiTi_(2)完全取代Ti_(2)Ni且均匀分布在钎缝中。当钎焊温度为1200℃时,钎焊接头的抗拉强度显著提高,最大抗拉强度为343 MPa。需特别指出的是,在不同钎焊温度下,溶解的TiAl母材中向外扩散的Al是影响钎焊接头组织演变和抗拉强度的主控因素。

关 键 词：γ-TiAl alloy micro-nano filler vacuum brazing interfacial microstructure tensile strength 

分 类 号：TG454[金属学及工艺—焊接]