Steady-state creep behavior of a Ti-25al-10Nb-3v-lMo alloy

Creep tests were conducted on Ti-25Al-10Nb-3V-1Mo alloy in the the temperature range of 913 - 1093 K at stresses ranging from 40 to 600 MPa. The creep behavior of the Ti₃Al alloy under these testing conditions revealed three different stress exponent regimes. In the temperature range of 1033 to 1093 K at low applied stress levels, the stress exponent was equal to 1.5. At the intermediate stress range (10₃<σ/E<3x10^-3), a stress exponent of 3.3 was exhibited indicating that the creep deformation was controlled by a viscous dislocation glide process As the applied stress increase, the stress exponent changed from 3.3 to 4.4 The activation energy for creep was equal to 288 kJ/mole in the region where viscous dislocation glide was the dominant deformation mechanism (n=3.3) In view of the diffusion data, the rate-controlling species in the viscous glide region was assumed to be Ti lattice diffusion