Abstract: Liquid state diffusion bonding between WC-6%Co and commercial superalloy Inconel 600 produced by brazing with 70Cu-30Zn (wt%) alloy reinforced with 10% of carbon nanotubes was studied. Experiments were carried out using a sandwich array of WC/Cu-Zn/Inconel 600 at temperatures of 980°C to 1000°C employing different holding times of 15-45 minutes under vacuum. Successful joints were formed at all temperatures and times without interfacial cracking and porosity. The joining occurred by the formation of liquid phase and a diffusion zone between the elements of the Inconel 600 (mainly Ni, Fe) and the filler metal. On the WC side, reaction occurred between the filler metal and Co from the cemented carbide. Scanning electron microscopy (SEM) micrographs showed the different diffusion layers formed in the reaction zone and that a narrow zone of carbon nanotubes was created at the center of the interlayer. Microanalysis (EDS) revealed precipitation of Cr carbides close to both the WC and the Inconel 600 interfaces.
Authors: G. Castro-Sánchez, G. Mendoza-Suarez, R. A.L. Drew, and J. Lemus-Ruiz
Keywords: brazing, sintering, interface, diffusion