Effects of brazing filler on properties of brazed joints between TiAl and metallic materials

The effects of brazing filler on the properties of brazed joints between TiAl and metallic materials were investigated, and potentially desirable brazing fillers and problems of this joint were demonstrated. Almost all of the brazing fillers investigated reacted to TiAl, with mainly an AlM2Ti type hard B2 intermetallic compound being formed inside brazed joints and at the boundaries to TiAl as a result of reactions of TiAl with Cu, Ni, and Au from the brazing fillers. From the standpoint of wettability to TiAl, as well as the microstructure and hardness of brazed joints, BAg-8 and BAu-12 showed possibilities for application in comparison with other commercial brazing fillers. Brazing of TiAl is considerably more difficult than for normal metallic materials because of its reactivity and the tendency to form a hard phase.