Modelling of the thermomechanical behaviour of FCC metals under various conditions

Modelling of the thermomechanical behaviour of FCC metals under various conditions

Ahmed Maati  El Hadj Ouakdi  Laurent Tabourot  Pascale Balland  Mourad Demouche 

Mechanical Laboratory, Amar Telidji University, Route de Ghardaia BP 37G 03000 Laghouat, Algeria

Laboratory of Physics and Mechanics of Metallic Materials, Sétif1 University, Setif1 19000, Algeria

SYMME Laboratory, Univ. Savoie Mont Blanc, FR-74000 Annecy, France

Corresponding Author Email:
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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

1. Introduction
2. Governing equations and constitutive model
3. Results and discussion
4. Conclusion and perspectives

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