Electroplastic behaviour in an aluminium alloy and dislocation density based modelling

Abstract

Electroplasticity refers to the application of controlled electric pulses during plastic deformation of materials. The electroplasticity phenomenon in metallic materials has led to the development of electrically assisted forming (EAF) process with improved formability. The lack of a suitable constitutive model to describe this electroplastic behaviour is a serious limitation in modelling and optimizing the EAF process. In the present work, a dislocation – density based constitutive model is developed for electroplastic deformation and is capable of predicting the effect of continuous and pulsed electric current during plastic deformation. Single- pulse electroplastic deformation experiments conducted on Al 5052 reveal similar mechanical behaviour as that predicted by the proposed model. The proposed model is also validated against published results for multiple electric pulses using Al 5052. The predicted results correlate well with the experimental data. Based on the predicted results, it is demonstrated that the long range softening observed in certain experiments results from the frequent application of electric pulses and is not due to any other internal softening mechanism.