Abstract: TiAl was diffusion bonded to Ti and TC4 alloy in vacuum furnace. Results showed,at the TiAl-Ti interface,the reaction layer of stratification Ti3Al was formed closest to TiAl base,and the a phase and the α + βphase arised closest to Ti base at 1173K and 1573K respectively. The phase structure of TiAl/ and the phase structure of TiAlwere observed be- tween AiAl and TC4 under respetive bonding temperature.The fiacture at tensile testing occurred in the bond - line, producing very flat fracture surfaces with some pull-out of the TiAl materials.The ultimate tensile strengths of the joint were approximate to γ-TiAl base marterial.

Key words: diffusion bonding, interface reacting, TiAl