Abstract E xperimental stress, strain and temperature histories are reported for annealed aluminium tubes undergoing torsional oscillations. These data show that heat is generated when aluminium responds as a non-linear material. It is necessary, therefore, to consider the coupling between the thermal and mechanical fields. A derivation of the coupled heat-conduction equation, with the rate of doing plastic work as a source term, is also presented. This equation is a generalization of the experimental results. It has an advantage over isothermal plasticity, in that conservation of energy is considered.