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Dissimilar joining of Ti3Al-based alloy to Ni-based superalloy has been carried out using gas tungsten arc (GTA) welding technology with Ti-Nb and Ti-Ni-Nb filler alloys. The joint welded with the Ti-Nb filler alloy contained much less interfacial brittle phases than the one using the Ti-Ni-Nb filler alloy. The average room-temperature tensile strength of the joint welded with Ti-Nb was 202 MPa and the strength value of the one welded with Ti-Ni-Nb was 128 MPa. For both fillers, the weak links of the dissimilar joints were the weld/In718 interfaces. The presence of TiNi, TiNi3 and Ni3Nb intermetallic compounds in the joint welded with Ti-Ni-Nb induced microcracks at the weld/In718 interface and deteriorated the mechanical properties of the joint. And the adoption of the Ti-Nb filler alloy decreased the formation tendency of interfacial brittle phases to some extent and thus enhanced the tensile strength of the joint.