Dislocation density based modelling of electrically assisted deformation process by finite element approach. (1st August 2022) - Tiwari, Jai
Abstract: Application of electric current, while deforming the material is known to aid the deformation process due to electroplastic effect. The experimentally observed behaviour during the application of electric current is generally correlated to the combined effect of Joule heating and localized electron–dislocation interaction. As the governing mechanism of electroplasicity lacks consensus, constitutive modelling of the said behaviour is challenging and scarce. The mathematical models reported in the literature often found to describe the electrically assisted deformation behaviour by only considering Joule's heating effect. A fully coupled thermal–metallurgical model is required to underpin the mechanism of electrically assisted deformation process. In this work, we are presenting a novel strategy to predict the electrical assisted deformation process by developing a fully coupled thermal and dislocation density based constitutive model. This modelling approach is implemented in a commercial finite element software using subroutines. The implemented model is evaluated to predict the electrical assisted deformation behaviour of aluminium alloys subjected to both continuous and pulsed current. The implemented model is able to successfully simulate the electrical assisted deformation process. Graphical abstract: Highlights: The coupled thermal and dislocation density based constitutive model is implemented in a finite element software as user subroutine to accommodate the electroplastic effect. The proposed model is validated for electric-assisted forming under the influence of continuous and pulsed current in aluminum alloys. Recovery behaviour during pulsing by dislocation annihilations is a unique feature of the model. The model is capable of fitting different mechanisms of electroplasticity. Independent effect of electric current on flow stress is accounted and validated by the model.