Microstructure and property of high-frequency induction brazed joints of titanium alloy TC4 and cemented carbide YG8

High-frequency induction brazing in vacuum was carried out between titanium alloy TC4 and cemented carbide YG8 by using copper based brazing filler metal B-Cu64MnNi at 920-970℃ for holding time of 20s. The microstructure, elements distribution and the phases of the joint were analyzed by SEM, EDS and XRD. The tensile strength of the joints was tested. The fracture surface morphologies and elements distribution were analyzed. The results indicate that the interface structure of the joints is composed of TC4/β-Ti/TiCu+Ti₃Cu₄+TiMn+Cu(Mn, Ni)/YG8, which shows an embedded structure when the temperature changes from 920℃ to 940℃. As the brazing temperature increases, the embedded structure is thus destroyed due to the overgrown brittle TiMn intermetallics, which also leads to the degradation of the mechanical properties. The maximum tensile strength of 206MPa is achieved at 930℃.