Current models for predicting the unusual deformation characteristics of Ni3Al alloys are based upon the idea of cross-slip pinning of screw dislocation segments. These models assume an Arrhenius type framework which employs a stress-modified activation barrier for forward cross slip. Use of such models has been successful in describing the orientation, asymmetry and temperature characteristics of yielding. A limitation of current models is their inability to predict the apparent lack of a strain rate effect in Ni3Al alloys. The current model approaches the problem using both kinetic and thermodynamic arguments to describe the physical process. It is then demonstrated that the driving force for cross-slip controls the process. The model describes all aspects of deformation including apparent strain rate insensitivity. An additional feature of the model is its ability to provide analytical and physical justification for the use of Arrhenius type equations for representing experimental data.