Microstructural evolution of infrared brazed Ti-15-3 alloy using Ti–15Cu–15Ni and Ti–15Cu–25Ni fillers

Microstructural evaluations of the infrared brazed Ti-15-3 alloy have been performed on as-brazed and post-brazing annealed samples. Microstructures of as-brazed joints consist of a Ti-rich phase alloyed with higher Cu and Ni content, a Ti-rich phase with lower Cu and Ni, and eutectoid two-phase structures. Post-brazing annealing modified the joint microstructure and the resulting microstructures depend on the filler composition, annealing temperature and time. Appropriate brazing process cycles can be developed to reduce or eliminate the presence of residual Cu–Ni rich Ti phase in the brazed joints using Ti–Cu–Ni filler metals.