INVESTIGATION OF THE REACTION ZONE BETWEEN TIAL AND MO

Pure Mo was incorporated in TiAl matrix via two different routes: (1) hot pressing of alternately sandwiched Ti-Al sheets and Mo foils; and (2) coextrusion and heat treatment of Ti-Al green compact and Mo rod. The reaction zone between TiAl and Mo is found to contain two intermet allic phases: beta-(Mo,Ti)Al and rho(Mo,Ti)(3)Al. The beta-rho boundar y is incoherent, whereas the TiAl-beta and rho-Mo boundaries are semic oherent. The reaction zone grows with increasing heat-treatment time i n a parabolic form. The incorporated Mo exhibits lower hardness than t he TiAl matrix, implying that ductilizing and toughening of TiAl by in troducing Mo as a ductile reinforcement are possible.