NUMERICAL MODELING OF THE PORTEVIN-LE CHATELIER EFFECT

A numerical model has been developed to describe the inhomogeneous deformation associated with the Portevin-Le Chatelier effect. The model is based on the transient behaviour of dynamic strain ageing resulting from the time dependence of the solute concentration at arrested dislocations. Spatial effects are included through a Bridgman-type factor which takes into account stress triaxiality effects at geometrical inhomogeneities. Numerically simulated stress-strain curves are shown to be in excellent agreement with experiment, with all of the important features of the Portevin-Le Chatelier effect being exhibited by the model.