Abstract
Thixoforming is a semi-solid metal forming process. It involves the transient behaviour of semisolids that depends on the solid fraction and the microstructure of the material before forming. Finite element simulations of thixoforming require constitutive equations accounted for this transient behaviour in relation with the material microstructure. In this paper, we propose a model based on a micromechanical approach and using homogenization techniques. It is an extension from a previous model initially developed to capture the isothermal and steady-state semisolid behaviour. We showed that the model describes very well the qualitative transient response highlighted via step-change up and step-change down in shear rate. In particular, the instantaneous response after a rapid change in shear rate is found to be associated with a constant internal structure and to follow a Newtonian behaviour. This result is in good agreement with some literature experimental results but contradicts others which reveal a shear thickening behaviour.
References
Atkinson HV (2005) Modelling the semisolid processing of metallic alloys. Prog Mater Sci 50:341–412
Peng H, Wang KK (1996) Steady-state and transient rheologiocal behaviour of a semi-solid tin-lead alloy in simple shear flow. In: 4th International Conference on Semi-Solid Processing of Alloys and Composites, 2–9
Modigell M, Koke J (2001) Rheological modelling on semi- solid metal alloys and simulation of thixocasting processes. J Mater Process Technol 111:53–58
Turng LS, Wang KK (1991) Rheological behavior and modeling of semi-solid Sn-15%Pb alloy. J Mater Sci 26:2173–2183
Quaak CJ, Katgerman L, Kool WH (1996) Viscosity evolution of partially solidified aluminium slurries after a shear rate jump. In: 4th International Conference on Semi-Solid Processing of Alloys and Composites, 35–39
Kumar P, Martin C, Brown SB (1994) Constitutive Modeling and Characterization of the flow behaviour of semi-solid metal alloy slurries – I The flow response. Acta Metall Mater 42:3595–3602
Martin C, Kumar P, Brown SB (1994) Constitutive modeling and characterization of the Flow Behaviour of Semi-Solid Metal Alloy Slurries – II The Structural Evolution under Shear Deformation. Acta Metall Mater 42:3603–3614
Favier V, Rouff C, Bigot R, Berveiller M, Robelet M (2004) Micro-macro Modeling of the Isothermal Steady-State Behaviour of Semi-Solids. Int J Form Processes 7:177–194
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Favier, V., Manceau, M. Transient semi-solid behaviour: modelling step-change up and step-change down in shear rate using a micromechanical approach. Int J Mater Form 2 (Suppl 1), 737 (2009). https://doi.org/10.1007/s12289-009-0626-2
Published:
DOI: https://doi.org/10.1007/s12289-009-0626-2