Effect of Bonding Temperature on Interfacial Microstructure and Properties of Zr/Ta Diffusion Bonded Joints

Abstract:

Zirconium alloys have garnered significant attention and widespread application in the nuclear industry due to their exceptional corrosion resistance and low thermal neutron absorption cross-section, particularly in dissolver equipment for highly corrosive environments. This study investigated the diffusion bonding interface microstructure between Zr-3 alloy and refractory metal tantalum as well as their mechanical properties. The effect of diffusion bonding temperature on the shear strength of zirconium/tantalum joints was examined. Additionally, the interface structure and fracture surface morphology of the joints were analyzed, and a preliminary study on the corrosion resistance of the joint was conducted. Results show that the typical interface structure of the joint is Zr/α-Zr+β-(Zr,Ta) solid solution/Ta, with the thickness of the diffusion layer increasing gradually as the bonding temperature rises. The shear strength of the joint initially increases and subsequently decreases with rising temperature. Under the bonding conditions of 900 °C-30 min-10 MPa, the joint strength reaches its maximum value of 385 MPa, with the fracture surface exhibiting mixed fracture characteristics. Furthermore, the zirconium/tantalum diffusion bonding joint demonstrates excellent corrosion resistance.