Braze joints in Ti-13.4Al-21.2Nb were made using several filler metal
compositions based upon the Ti-Cu-Ni ternary system. Specimens were va
cuum brazed, using filler metal pre-placed between bonding surfaces. T
wo types of braze foil, one produced by rapid solidification technique
s and one formed by a roll bonding process, were examined. Mechanical
test results indicated that substantial differences in braze joint str
ength could be obtained From specimens prepared using foil manufacture
d by the two different processes. Specifically, for the higher alloyed
composition, a laminated foil produced joints with lower room tempera
ture tensile strength compared to its rapidly solidified counterpart.
Specimens prepared using laminated foil typically failed through the b
raze joint and had low strength. This behavior was related to the pres
ence of an increased amount of centerline alpha-two phase in the braze
joints made using the laminated filler metals. The formation of this
microstructural feature was influenced by segregation of the filler me
tal alloying elements, nickel and copper. Braze joints prepared using
laminated foils exhibited higher levels oi segregation, even after lon
g hold times at the brazing temperature, than joints made using rapidl
y solidified foil.