Strong bonding of infrared brazed α2-Ti3Al and Ti-6Al-4V using Ti-Cu-Ni fillers

Infrared dissimilar brazing of α2-Ti3Al and Ti-6Al-4V using Ti-15Cu-25Ni and Ti-15Cu-15Ni filler metals has been performed in this study. The brazed joint consists primarily of Ti-rich and Ti2Ni phases, and there is no interfacial phase among the braze alloy, α2-Ti3Al and Ti-6Al-4V substrates. The existence of the Ti2Ni intermetallic compound is detrimental to the bonding strength of the joint. The amount of Ti2Ni decreases with increasing brazing temperature and/or time due to the depletion of Ni content from the braze alloy into the Ti-6Al-4V substrate during brazing. The shear strength of the brazed joint free of the blocky Ti2Ni phase is comparable with that of the α2-Ti3Al substrate, and strong bonding can thus be obtained.