Brazing Titanium Filler Metals

Copper foil 0.0007” (17 microns) thick is supplied as a filler metal for vacuum brazing titanium to aluminum alloys A3003, A6061, and others. Liquid Al-Cu braze alloy is formed during brazing due to the eutectic reaction in contact of copper foil with the aluminum base metal. The Al-Cu liquid braze alloy reacts with titanium base metal too, providing excellent wetting of both base metals and flow in the joint gap. The structure of brazed joint is shown in picture below. Copper foil preforms can be used together with aluminum foils TiBrazeAl-600 (Al-12Si) or TiBrazeAl-665 (Al-2.5Mg) see Table 3-1, above. Titanium and aluminum parts to be brazed should be slightly compressed during brazing in order to provide contact of base metals with copper foil or aluminum-copper laminated foils that are used as filler metals. Compositions of brazing filler metals that can be obtained when using these three foils in different combinations are presented in Table 4.