Kinetics and statistics of jerky flow: experiments and computer simulations

The paper presents an overview of experimental and theoretical studies of the Portevin-Le Chatelier effect with regard to the statistics of stress discontinuities and spatio-temporal behaviour of strain localisations. It is shown that the statistics of stress drops changes progressively from peak-shaped to monotonie distributions when the strain rate or temperature are increased. A mesoscopic model accounting for strain inhomogeneity and spatial coupling is proposed to explain the statistical behaviour observed. The model reproduces the character of deformation curves and the corresponding deformation band kinetics. It also predicts the caracteristics of the bands for both constant strain rate and constant stress rate experiments.