On temperature scaling in dislocation plasticity

Abstract

Macroscopic theory of dislocation plasticity must respect the scaling properties of underlying dislocation dynamics. In this paper the scaling properties of dislocation dynamics involving temperature and Burgers vector are found. The scaling properties are established in a limited setting of dynamical equations, and it is conjectured that they should hold in general case. This conjecture is supported by a compilation of experimental data for steady state stresses and Voce stresses. In order to describe the emerging scale-invariant experimental dependencies, it is suggested a scale-invariant form of stress–strain rate–temperature constitutive relation. It also obeys to another feature of dislocation dynamics, a nontrivial rigid-viscous limit when thermal fluctuations go to zero. The constitutive equation yields a reasonable fit of experimental data.