Vacuum diffusion bonding between titanium alloy TC4 and austenitic stainless steel 1Crl8NigTi was carried out by using conventional and ladder-like processing methods with Ni + Nb as interlayers. The microstructure and elements distribution of the joints were analyzed by OM, SEM and EDS. The mechanical properties of the joints were characterized by tensile strength test. Meanwhile the fracture surfaces were analyzed too. The results showed that Ni + Nb interlayers successfully prevent the formation of Fe-Ti intermetallic compounds, the microstructures of the transient joint from 1 CrlSNigTi to TC4 are Fe-Cr-Ni solid solution, NJ-Nb reaction layer,residual Nb and Nb-Ti solid solution. The weld quality of ladder-like processing joints are superior to the conventional processing joints. The maximum strength of 396MPa at 900℃ was achieved by using ladder-like processing method. The fractures occured on the mixed reaction layer that was formed by Ni3Nb and a small amount Ni6Nb7 between Ni and Nb, and this layer played a crucial role to the joint.%分别采用常规工艺和阶梯状工艺的方法,对添加Ni+Nb复合中间层的TC4钛合金与1Cr18Ni9Ti不锈钢真空扩散焊进行了研究.利用光学显微镜(OM)、扫描电镜(SEM)以及能谱分析(EDS)对接头的组织结构、元素分布进行了分析,测试了接头的力学性能并分析了断口形貌和元素分布.结果表明,通过添加Ni+Nb中间层成功阻止了Fe-Ti金属间化合物生成,接头界面过渡区组织自不锈钢侧依次为Fe-Cr-Ni固溶体、Ni-Nb反应层、剩余Nb及Nb-Ti固溶体.阶梯状工艺下接头的结合质量明显优于常规工艺下的接头,在阶梯状工艺上限温度900℃条件下接头抗拉强度达到了396MPa,断口分析表明,接头断裂于Ni-Nb形成的反应层,该反应层是由Ni,Nb和少量Ni6Nb7金属间化合物组成的混合层,为接头过渡区关键环节.
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