Abstract
In order to improve high temperature property of the dissimilar joint between 0.5%Ti-0.07%Zr-Mo and graphite, Nb-Ti and Nb insert metals as well as a conventional Zr diffuse material were used for bonding. Cross-sectional observation and EPMA analysis were carried out to evaluate the joining process. Mo did not diffuse into bonding layer at low joining temperature. However, diffusion of Mo into bonding layer was significantly observed at high joining temperature. For Nb-Ti insert metal, Ti-rich dendritic Ti-Nb-C solid solution layer was formed near the graphite side in bonding layer. This layer indicated high hardness. Diffusion of Mo from 0.5%Ti-0.07%Zr-Mo suppressed growth of the Ti-Nb-C solid solution layer at joining temperatures above 2073K. The joint with Nb-Ti insert metal indicated higher bending strength than that of the joint with Zr solder material above 1673K.
