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In the present work,the dissimilar joining of a Ti_3AI-based alloy to a Ni-based superalloy was attempted by gas tungsten arc(GTA) welding technology.Sound joints were successfully achieved by using a Cu—Ni alloy as filler material.According to X-ray energy dispersive spectroscopy and X-ray diffraction analysis results three transitional layers at the weld/Ti_3AI interface were verified as follows:Ti_2AINb phase dissolved with Cu and Ni;AI(Cu,Ni)_2Ti,(Cu,Ni)_2Ti and(Nb,Ti) solid solution;Cu-rich phase and a complex multi-element phase.The In718/weld interface is characterized by solid solutions of Ni,Cu,Cr,Fe and Nb.The average tensile strength of the as-welded joints at room temperature is 1 63 MPa,and after a post—weld heat treatment it is increased slightly to 177 MPa.The fracture occurred at the surfacial layer of the joined Ti_3AI base alloy,indicating that the Ti_2AINb layer dissolved with Cu and Ni is the weak link of the Ti_3AI/ln71 8 joint.
In the present work, the dissimilar joining of a Ti_3AI-based alloy to a Ni-based superalloy was attempted by gas tungsten arc (GTA) welding technology. Ground joints were successfully achieved by using a Cu-Ni alloy as filler material. According to X-ray energy dispersive spectroscopy and X-ray diffraction analysis results three transitional layers at the weld / Ti_3AI interface were verified as follows: Ti_2AINb phase dissolved with Cu and Ni; AI (Cu, Ni) _2Ti, (Cu, Ni) _2Ti and (Nb, Ti) solid solution; Cu-rich phase and a complex multi-element phase. The In718 / weld interface is characterized by solid solutions of Ni, Cu, Cr, Fe and Nb. The average tensile strength of the as-welded joints at room temperature is 1 63 MPa, and after a post-weld heat treatment it is increased slightly to 177 MPa. The fracture occurred at the surfacial layer of the joined Ti_3AI base alloy, indicating that the Ti_2AINb layer dissolved with Cu and Ni is the weak link of the Ti_3AI / ln71 8 joint.