The main objective of this study is to propose a physics-based modelling adapted to describing the thermomechanical behaviour of metal alloys (specifically FCC metals). This approach takes into account the prominent phenomena generated by plastic deformation. Because of its specific mechanical and physical properties (ductility, lightness, etc.), this study is conducted on 1050 aluminium sheets widely used in sheet metal forming sector. The effect of two opposite and simultaneous physical phenomena on plastic deformation has been highlighted: the strain hardening rules that occurs because of dislocation movements and dislocation multiplication within the crystal structure of the metal and the dynamic recovery governed by thermal activation at intermediate temperatures (T≥0,4Tm). The evolution of two internal state variables (dislocation density and subgrain size) under different loading conditions was investigated. A Fortran program was used to identify the constitutive model parameters. To validate the present model, the curves obtained by numerical method were compared with those obtained by experimental traction data derived from literature.
In a wide range of strain rates and temperatures, the obtained results show that the proposed model is effective in predicting the thermomechanical behaviour in traction for FCC metals due to the good agreement between calculated and experimental data. The results show that the strain hardening decrease significantly with increase in temperature and/or decrease in strain rate which explains dominance of dynamic recovery at elevated temperatures.
Based on research conducted in the field, some proposals were introduced in the study to contribute to the improvement of numerical results and attempt to expand the use of the model for other types of loading (creep for example whose study is underway)
dislocation density, dynamic recovery, strain hardening, subgrain size, thermomechanical behaviour
Davenport S. B., Higginson R. L. (2000). Strain path effects under hot working: an introduction. Journal of Materials Processing Technology, Vol. 98, No. 3, pp. 267-291. https://doi.org/10.1016/S0924-0136(99)00320-9
Ferron G., Ouakdi E. H. (1988). A state-variable modelling of the viscoplastic behaviour and of the necking behaviour of aluminium. Strength of Metals and Alloys, vol. 2 pp. 1019-1024. https://doi.org/10.1016/B978-0-08-034804-9.50161-3
Haupt P. (2000). Continuum mechanics and theory of materials. Continuum Mechanics and Theory of Materials.
Jiao Y., Liu H., Wang X., Zhang Y., Luo G., Gong Y. (2014). Temperature effect on mechanical properties and damage identification of concrete structure. Advances in Materials Science and Engineering, Vol. 2014. http://dx.doi.org/10.1155/2014/191360
Kiritani M., Sota T., Tawara T., Arimura H., Yasunaga K., Matsukawa Y., Komatsu M. (2010). Defect structures introduced in FCC metals by high-speed deformation. Radiation Effects and Defects in Solids, Vol. 157, No. 1-2, pp. 53-74. https://doi.org/10.1080/10420150211397
Klepaczko J. R. (1987). Proceedings of the 8th, RISO. Symp. on metallurgy and materials science, Denmark.
Lissel L. (2006). Modelling the microstructural evolution during hot working of C-Mn and of Nb micro-alloyed steels using a physically based model. Doctoral Thesis, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
Luthy H., Miller A. K., Sherby O. D. (1980). Fundamentals of creep in metals and alloys. Acta Metall., Vol. 28, pp. 169.
McQueen H. J., Hockett J. E. (1970). Microstructures of aluminium compressed at various rates and temperatures. Metallurgical Transactions, Vol. 1, No. 11, pp. 2997-3004. https://doi.org/10.1007/BF03038412
Ouakdi E. H. (1988). Modélisation physique du comportement plastique de l'aluminium à moyenne température. Application à l'étude de la striction, Doctoral Thesis, Metz University.
Ouakdi E. H., Louahdi R. (1996). A physical model describing the visco-plastic behaviour of aluminium under tension and under creep for T > 0.4Tm. Journal of Materials Science Letters, Vol. 15, No. 17, pp. 1555-1557. https://doi.org/10.1007%2FBF00625021
Ouakdi E. H., Louahdi R., Ferron G. (1998). A constitutive model describing the necking behaviour of aluminium during tension and creep. Journal of Materials Science Letters, Vol. 17, No. 3, pp. 193-196. https://doi.org/10.1023%2FA%3A1006571909042
Priester L. (2012). Interactions between dislocations and grain boundaries. Grain Boundaries, Vol. 172. https://doi.org/10.1007/978-94-007-4969-6_8
Rodríguez-Martínez J. A., Rodríguez-Millán M., Rusinek A., Arias A. (2011). A dislocation-based constitutive description for modelling the behaviour of FCC metals within wide ranges of strain rate and temperature. Mechanics of Materials, Vol. 43, No. 12 pp. 901–912. https://doi.org/10.1016/j.mechmat.2011.09.008
Sene N. A., Balland P., Tabourot L., Vautrot M., Ksiksi N. (2016). An original prediction of localization during tensile and biaxial expansion tests on copper by the compartmentalized model. AIP Conference Proceedings, Vol. 1769, No. 1. https://doi.org/10.1063/1.4963553
Shimokawa T., Kitada S. (2014). Dislocation multiplication from the frank-¬read source in atomic models. Materials Transactions, Vol. 55, No. 1, pp. 58-63. https://doi.org/10.2320/matertrans.MA201319
Tabourot L., Maati A., Balland P., Vautrot M. (2015). Influence of heterogeneities and of their distribution on the elastoplastic behaviour of metals, International symposium on plasticity