Modelling steady state deformation of fcc metals by non-equilibrium thermodynamics

Abstract

The steady state of plastic deformation is modelled by non-equilibrium thermodynamics theory. Based on energy conservation and constant entropy requirements at the steady state, the saturation dislocation density ρ is found to be determined by ρ=λ ?/(bv _c), where λ is a constant that depends on the material properties, ? is the strain rate, b is the magnitude of Burgers vector and v _c is the dislocation climb velocity along the dislocation line. Then, by employing the Taylor relation, the saturation flow stress is obtained. The model is applied to four pure fcc single crystals under tensile testing and polycrystalline Al at steady state creep. The predictions are in good agreement with the experimental observations.