The creep characteristics, including the nature of the creep transient after a stress reduction and activation energy for creep of single crystalline Ni3Al(Ta,B) were investigated at 1083 to 1388K,. An inverse type of creep transient was observed during stress reduction tests in the creep regime where the stress exponent was equal to 3.2. The activation energy for creep in this regime was equal to 340kJ/mol. A normal type of creep transient was observed during stress reduction tests in the regime where the stress exponent was equal to 4.3. The activation energy for creep in this regime was equal to 530kJ/mol. The different transient creep behavior and activation energies for creep observed in this investigation were consistent with the previous suggestion that the n = 4.3 regime was associated with creep controlled by dislocation climb, whereas the n = 3.2 regime was associated with a viscous dislocation glide process for Ni3Al at high temperatures.

Creep Characteristics of Single Crystalline Ni3Al(Ta,B). Wolfenstine, J., Kim, H.K., Earthman, J.C.: Metallurgical and Materials Transactions A, 1994, 25[11], 2477-82