Study on vacuum brazing of DD3 Ni-base superalloy and Ti₃AlC₂ ceramic

By comparison,an appropriate brazing filler metal was selected and applied to the follow-on experiments. DD3 Ni-base superalloy and Ti₃AlC₂ ceramic were successfully brazed in vacuum using Ag-Cu-Ti as filler metal in a temperature range of 800~900℃ for 10 min. The interfacial microstructure of the brazed joints was investigated by adopting scanning electron microscope,energy dispersive spectroscopy and X-ray diffraction. The result showed that the typical interfacial microstructure of the joints can be described as DD3/AlNi/Al₃(Ni,Cu) ₅+Al(Ni,Cu)+Ag_ss/(Al,Ti)₃(Ni,Cu)₅/Al₄Cu₉+AlNi₂Ti+Ag_ss/TiAg/Ti₃AlC₂. Through the mechanical properties test of the joints,a maximum shear strength value of 135.9 MPa was obtained when the joint was brazed at 850℃ for 10 min. The fracture occurred at the Ti₃AlC₂ ceramic side adjacent to the brazed seam during the shear test. The interfacial microstructure of the joints was similar to each other,while the shear strength decreased when reduces or improves the brazing temperature.