Interfacial microstructure of induction brazed joints of TiAl-based intermetallics to steel 35CrMo with AgCuNiLi filler

TiAl-based intermetallics joined by induction brazing using Ag-Cu-Ni-Li filler at 850-970 °C for 1-10 min was investigated. According to the experimental observations, when the brazing temperature is low and the brazing time is short, the joint microstructure is TiAl alloy/AlCuTi with TiCu/Ag-base solid solution + AlCu2Ti with TiCu/Cu-rich phase/Al(Cu, Ni)2Ti phase with (Cu, Ni)-Ti/Ag-Cu hypoeutectic microstructure/diffusion layer close to steel (FeTi phase contained)/35CrMo steel; when the brazing temperature is low and the brazing time is long, the joint microstructure is TiAl/AlCuTi with TiCu/AlCu2Ti with TiCu/Ag-base solid solution + AlCu2Ti with TiCu/Ag-base solid solution + Al(Cu, Ni)2Ti phase with (Cu, Ni)-Ti/diffusion layer close to steel/35CrMo steel; when the brazing temperature is high and the brazing time is short, the joint microstructure is TiAl alloy/AlCuTi with TiCu/AlCu2Ti with TiCu/Cu-base solid solution + Ag-base solid solution/(AlCu2Ti phase with TiCu + Cu-base solid solution) + Ag-base solid solution/Al(Cu, Ni)2Ti phase with (Cu, Ni)-Ti (Ag solid solution) + Ag-base solid solution/diffusion layer close to steel/35CrMo steel.