Creep behavior of an oxide dispersion strengthened Ni3Al ordered intermetallic material

An alternative description of the high temperature creep behavior of oxide dispersion strengthened ordered Ni3Al material, to that recently given by Klotz et al., is presented in this paper. This material shows much higher values of apparent stress exponent and apparent activation energy than those of the oxide dispersion free material. Analysis of these data following the Arzt detachment model yield to good model predictions only at high temperature, whereas at low temperature the predictions deviate from the experimental data. In agreement with Klotz et al., a threshold stress approach is not appropriate to describe the creep behavior of the investigated material and it is concluded that the creep behavior is controlled by the interaction between dislocations and oxide particles. However. this interaction is best described by a temperature independent stress exponent, (n) over tilde. The (n) over tilde model, which considers that this interaction raises the oxide-dispersion free material stress exponent by a value of (n) over tilde, inducing higher apparent activation energy values at high temperatures, satisfactorily describes the experimental data. (C) 2000 Published by Elsevier Science S.A. All rights reserved.