Abstract: TiAl and 40Cr is induction brazed with Ag-Cu-Ti filler metal in a vacuum furnace. The microstructure and mechanical properties of the joints is studied. The kinds of formation phases and the interface structures of the joints are investigated by scanning electron microscopy (SEM), electron probe microanalysis (EPMA) and X-ray diffraction (XRD), the joint strength is determined by tensile testing method and the microhardness of the formation phases is tested. Results show that three formation phases, TiAl3, Ag[s,s], Ti(Cu,Al)2, have occurred in the brazing seam. The interface structure of the joints brazed at 1 143~1 183 K can be described as TiAl / TiAl3/ TiAl3+Ag[s,s]/Ti(Cu,Al)2 + Ag[s,s] / Ag[s,s] + Ag-Cu eutectic phase / 40Cr and the interface structure of the joints brazed at 1 223 K can be described as TiAl / Ti(Cu,Al)2+ some Ag[s,s] / Ag[s,s]+ Ag-Cu eutectic phase / 40Cr. An excellent joint tensile strength as high as 267 Mpa is obtained when induction brazed at 1 143 K for 5 min.

Key words: 40Cr, Induction brazing, Interface structure, Tensile strength, TiAl