Effects of strain rate on the characteristics of PLC deformation bands for AA5083-H116 aluminium alloy
Résumé
An experimental, theoretical and numerical investigation of the Portevin-Le Chatelier (PLC) effect in the aluminium alloy AA5083-H116 is undertaken in this paper. Five different tests at different overall strain rates are carried out on smooth flat specimens in order to exhibit the effects of strain rate on the characteristics of the deformation bands and their propagation. Both digital image correlation and digital infrared thermography are used to capture and characterize the spatio-temporal features of the PLC behaviour. Inhomogeneous deformation with various localization bands caused by the PLC effect is observed in all the tests and the formation, evolution and propagation of these deformation bands are visualized allowing their characteristics to be measured. An elasto-viscoplastic constitutive model, developed for metals exhibiting dynamic strain ageing, is used to represent the material behaviour. Linear stability analysis with the adopted constitutive model is shown to give the orientations of the bands, but fails to predict the critical strain at which serrated yielding occurs. Finally, the model is used in 3D numerical simulations of the physical tests using explicit finite element analysis. The numerical results are compared with the experimental observations and the main deviations between tests and simulations are discussed.
Origine : Fichiers produits par l'(les) auteur(s)
Loading...