Microstructure and mechanical properties of transparent alumina and TiAl alloy joints brazed using Ag-Cu-Ti filler metal

In this study, transparent alumina and TiAl alloy were successfully brazed at 860°C-940 °C using Ag-21Cu-4.5Ti (wt%) filler metal. The microstructure and mechanical properties of the joints were investigated. SEM and TEM analysis showed the typical interfacial microstructure of the joints brazed at 900 °C for 5min was TiAl/β-Ti + AlCuTi/AlCu2Ti + AlCuTi/AlCu2Ti + Ag(s,s) + Cu(s,s)/(Cu,Al)3Ti3O/transparent alumina. The effects of brazing temperature and holding time on the microstructure and mechanical properties of TiAl/transparent alumina joint were studied. In addition, the effects of the dissolution and diffusion of TiAl on the microstructural evolution of the brazing seam were discussed. Shear strength analysis reveals that the shear strength of the joint increases at first and then decreases when brazing temperature rises. The maximum shear strength is 49 MPa when the joint is brazed at 900 °C for 5 min.