Creep characteristics of single crystalline Ni3Al(Ta,B)

Abstract

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) in the temperature range 1083 to 1388 K, were investigated. An inverse type of creep transient is exhibited during stress reduction tests in the creep regime where the stress exponent is equal to 3.2. The activation energy for creep in this regime is equal to 340 kJ mol−1. A normal type of creep transient is observed during stress reduction tests in the regime where the stress exponent is equal to 4.3. The activation energy for creep in this regime is equal to 530 kJ mol−1. The different transient creep behavior and activation energies for creep observed in this investigation are consistent with the previous suggestion that then = 4.3 regime is associated with creep controlled by dislocation climb, whereas then = 3.2 regime is associated with a viscous dislocation glide process for Ni3Al at high temperatures.