We describe two cases in which constitutive laws for deformation kinetics are available that are both physically well founded and experimentally well obeyed. New experiments on Al-Mg alloys, in the regime of viscous deformation, fit the solute drift equation very well, with n-3 and Q{sub D} unadjustable; they do not fit the solute drag model. The high-stress regime, as well as all data for pure copper, fit the model of hardening and dynamic recovery, at least up to temperatures of 0.6 T{sub m}. In both cases, dynamic recrystallization occurs at high temperatures. It seems to follow rather than determine the deformation kinetics
