[en] The Equal Channel Angular Extrusion process is used to modify the microstructure of an AA1050 aluminum alloy in order to produce an ultra fine grained material. Due to the severe plastic deformation undergone by the material during the ECAE process, the subsequent behavior of the material is non-conventional and difficult to model with classical constitutive laws (e.g. ECAE aluminum presents a large initial back-stress which must be adequately incorporated in the model). In this study, the evolution of the back-stress during the ECAE process is analyzed. Two different numerical models were investigated in this respect. The first one is a single crystal strain gradient plasticity model based on dislocation densities. The second model is the Teodosiu and Hu’s hardening model, which is a microstructuraly based phenomenological model at the macroscale. The results provided by the two models are obviously distinct. Nevertheless, some common trends can be pointed out, among which the amplitude of the back-stress that is similar. In agreement with the cyclic deformation mode of the studied route C ECAE process, the evolution of the predicted back-stress is also cyclic in both models.
Disciplines :
Civil engineering
Author, co-author :
Duchene, Laurent ; Université de Liège - ULiège > Département Argenco : Secteur MS2F > Département Argenco : Secteur MS2F
Geers, M. G. D.
Brekelmans, W. A. M.
Chen, E.
Verlinden, Bert
Habraken, Anne ; Université de Liège - ULiège > Département ArGEnCo > Département ArGEnCo
Language :
English
Title :
Multiscale modeling of equal channel angular extruded aluminium with strain gradient crystal plasticity and phenomenological models
Publication date :
2008
Event name :
15th International Conference on the Texture of Materials (ICOTOM-15)
Event place :
Pittsburgh, United States
Event date :
2008
Audience :
International
Main work title :
Proceedings of the 15th International Conference on the Texture of Materials (ICOTOM-15)
Hall, E. O., The deformation and aging of mild steel: iii. Discussion of results. Proc. Physical Society of London, B64, 747-753 (1951).
Poortmans, S. and Verlinden, B., Mechanical properties of fine-grained AA1050 after ECAP. Materials Science Forum 503-504, 847-852 (2006).
Teodosiu, C., Hu, Z., Evolution of the intragranular microstructure at moderate and large strains: modeling and computational significance. In Proc. NUMIFORM 95, edited by Shen, S. F. and Dawson, P. R., pp. 173-182 (1995).
Bouvier, S., Teodosiu, C., Haddadi, H. and Tabacaru, V., Anisotropic Work-Hardening Behaviour of Structural Steels and Aluminium Alloys at Large Strains. In: Proc. of the Sixth European Mechanics of Material Conference (EMMC6), S. Cescotto Eds, 329-336 (2002).
Evers, L. P., Brekelmans, W. A. M., Geers, M. G. D., Non-local crystal plasticity model with intrinsic SSD and GND effects. J. of the Mechanics and Physics of Solids, 52, 2379-2401 (2004).
Evers, L. P., Brekelmans, W. A. M., Geers, M. G. D., Scale dependent crystal plasticity framework with dislocation density and grain boundary effects. International Journal of solids and structures, 41, 5209-5230 (2004).
Bayley, C. J., Brekelmans, W. A. M., Geers, M. G. D., A comparison of dislocation induced back stress formulations in strain gradient crystal plasticity. International Journal of Solids and Structures, 43, 7268-7286 (2006).
Bayley, C. J., Brekelmans, W. A. M., Geers, M. G. D., A three-dimensional field crystal plasticity approach applied to miniaturized structures. Philosophical Mag., 87 (8-9), 1361-1378 (2007).
Li, S., Hoferlin, E., Van Bael, A., Van Houtte, P., Teodosiu, C., Int. J. Plast. 19, 647-674 (2003).
Bouvier, S., Alves, J. L., Oliveira, M. C., Menezes, L. F., Comp. Mater. Sci. 32, 301-315 (2005).
Alves, J. L., Oliveira, M. C., Menezes, L. F., An advanced constitutive model in sheet metal forming simulation: the Teodosiu microstructural model and the Cazacu Barlat yield criterion. In Proc. NUMIFORM, edited by Ghosh, S. et al., A1P Conf. Proc. 712, pp. 1645-1650 (2004).
Fülöp, T., Brekelmans, W. A. M., Geers, M. G. D., Size effects from grain statistics in ultrathin metal sheets. Journal of Materials Processing Technology 174, 233-238 (2006).
Flores, P., Duchêne, L., Bouffioux, C., Lelotte, T., Henrard, C., Pernin, N., Van Bael, A., He, S., Duflou, J., Habraken, A. M., Model Identification and FE Simulations: Effect of Different Yield Loci and Hardening Laws in Sheet Forming. Int. J. of Plasticity, 23 (3), 420-449 (2007).
