Dislocation dynamics in carbon-doped titanium aluminide alloys

Different thermal treatments were conducted on carbon containing two-phase titanium aluminide alloys to obtain solid solution and precipitation hardening effects. The strengthening mechanisms were characterized by activation parameters of the glide processes and electron microscope observations. Carbon in solid solution was found to be less efficient than carbide precipitates for hardening the material. Fine dispersions of Ti3AlC perovskite precipitates form arrays of strong glide obstacles so that perfect and twinning partial dislocations were effectively pinned. This mechanism results in a high athermal contribution to the flow stress, which significantly improves the high temperature strength of the material.