Temperature-dependent structure of {bold a}(10{bar 1}) superdislocations in Ni{sub 3}Al

The dissociated structure of the a(101) superdislocations in Ni{sub 3}Al is predicted as a function of temperature. The temperature dependence of the relevant fault Helmholtz free energies and elastic constants are calculated within the quasiharmonic approximation using the embedded atom method, Results of these calculations are then incorporated into anisotropic elasticity theory-based calculations of the dissociation distances. The cross-slip activation enthalpy is estimated and found to decrease by 24% at 600 K when compared with its 0 K value. The calculations point to the need to perform experiments to address this temperature dependence