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.