A New Suggestion of Creep Deformation Mechanism of TiAl

초록

Creep deformation behavior in lamellar TiAl alloys have been investigated. As in the case with metals, the normal primary creep stage was observed. However, as creep strain increased within primary regime, we found that dislocation density decreased and creep activation energy increased from the value of the activation energy of self-diffusion of Ti in TiAl(300kJ/mol) to a value of about 380kJ/mol. This was measured as the activation energy for steady state creep deformation. A small amount of prestrain was found to be responsible for the reduction of initial dislocation density. In addition, this prestrained specimen showed significantly reduced primary creep strain and the creep activation in the primary stage was mesured as about 380kJ/mol. These results clearly confirm the creep deformation mechanism of lamellar TiAl alloys proposed here.