Microstructure and Property of N5 Single Crystal Superalloy Joints Bonded by Transient Liquid Phase Diffusion Bonding

Abstract

N5 single crystal was transient liquid phase (TLP) diffusion bonded under different conditions in vacuum environment using Ni-base insert metal. Scanning electron microscopy (SEM) was used to observe the microstructure of the joints. Results show that the typical TLP joint could be divided into rapidly solidified zone (RSZ), isothermally solidified zone (ISZ) and diffusion zone (DZ). The widths of RSZ decreases with the increase of holding time at any established bonding temperature, amount of bulk compounds decrease at the same time. Bonding temperature has a complex influence on TLP joint. High temperature creep rupture tests were performed, results reveal that the sample fractured in the joint interface and the fracture mechanism has been studied.