Transient liquid phase diffusion bonding of Cu-Ni alloy mild steel composite pipe

Composition, microstructure and performance of the TLP diffusion bonding zone of B10 Cu-Ni alloy low carbon steel using H62 brass interlayer were examined by means of SEM and OM, EDX analysis, microhardness test, shear test and alternating bend test.Sound bonding was obtained between the two dissimilar materials at 950-1 000℃ for 0.5-2 h.At the brass cupro-nickel interface, and composition changed gradually, and grains grew continuously, and no remarkable hardness change was detected.On the other hand, significant variation of composition was observed at the steel brass interface.Pearlite-rich band was found parallel to the bonding line in the region of steel adjacent to the interface.As the time and or temperature increased, iron-rich microstructure with higher hardness, resulting in a decrease of plasticity of the interface, was observed,.