Microstructural and Corrosion Properties of Ti-to-Zr Dissimilar Alloy Joints Brazed with a Zr-Ti-Cu-Ni Amorphous Filler Alloy

Titanium and Zircaloy-4 dissimilar alloys were brazed with a zirconium-titanium-copper-nickel amorphous filler alloy, the resulting joint structures as well their corrosion properties examined. The microstructure of joints was investigated according to brazing holding time at 850 °C, property analyzed by potentiodynamic polarization. During brazing, produced diffusion-induced isothermal solidification molten alloy. At relatively brief 5 min, large segregation zone consisting an active ?-phase nobler intermetallic phase generated in center, which suffered from micro-galvanic corrosion. presence alloyed titanium deteriorated nobility ?-zirconium near induced galvanic coupling cathodic base metals, massive localized This caused pitting behavior applied potential ?51.1~187.5 mV during anodic With 20 concentration alloying elements homogenized eliminate electrochemical difference minimize susceptibility region. homogeneous resulted highly passive comparable that metal.