Because previous temperature change tests could not be continued to large strains, the effects of a low temperature prestrain on the large strain flow curve at a higher temperature have been found by extrapolation. These extrapolations have been based on the assumption that after prestraining at a lower temperature the stress-strain curve would rejoin the stress-strain curve obtained at a constant temperature. The temperature change tests described however, show this assumption to be false. The prestrained samples have a flow curve which is higher and parallel to that for the constant temperature test, indicating the important result that some elements in the dislocation substructure cannot be dynamically recovered. Additionally, a dislocation structure which does not recover when deformation is continued at a higher temperature (but still within the low temperature regime) demonstrates the limitations of dynamic recovery.