Effects of Using Amorphous Interlayers on Liquid Phase Diffusion Welding Process

Abstract

Effects of the morphology and composition of nickel-base interlayers on the transient liquid phase diffusion weldability of superalloy Inconel 713C have been investigated by microscopy, electron probe microanalysis and high temperature strength tests of the joints.
Proper composition adjustment, powder refinement and homogenization of the interlayers were indicated to be both important for the improvement of the weldability. Especially in amorphous interlayers made by the rapid quenching liquid metal method, the composition homogeneity which contributes to easy homogenization of the joints was fairly improved without segregation of molybdenum and hafnium. Additionally, in case of using amorphous interlayers, the thickness of liquid layer formed at the joint interface during welding was revealed to become thinner compared with the case of using powdered interlayers, so that the isothermal solidification of the liquid phase could occur more rapidly. These phenomena were demonstrated to result in increasing the joint strength, and some of the joints showed 100 percent joint efficiency in stress-rupture tests.