Interfacial microstructure and properties of the self-joined Zircaloy-4 joints with Ni foil

Ni foil is used as interlayer to join Zircaloy-4 by transient liquid phase bonding. The Zone_β→α is formed in the joints and its width increases with temperature. The formation of Zone_β→α is controlled by both bonding temperature and Ni concentration. The Zone_β→α is mainly composed of primary Zr phase and eutectic Zr(Zr₂Ni) structure. The micro-hardness of the joints mainly depends on the precipitates and the size of α-Zr phase. The non-planar bonding interfaces are developed in the joints when the bonding temperature above 960 °C. Resulting from the non-planar bonding interfaces, the maximum shear strength of the joints is 358 ± 19 MPa