  A simple extension of the thermodynamic dislocation theory to non-uniform
plastic deformations is proposed for an analysis of high-temperature torsion of
aluminum bars. Employing a small set of physics-based parameters, which we
expect to be approximately independent of strain rate and temperature, we are
able to fit experimental torque-twist curves for five different twist rates and
at one fixed ambient temperature. We find that thermal softening due to
temperature rise is significant at high twist rates.
