Role of intragranular microstructure development in the macroscopic behavior of multiphase steels in the context of changing strain paths

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:517

Article

Franz, Gerald¹  Abed-Meraim, Farid¹  Zineb, Tarak Ben²  Lemoine, Xavier³  Berveiller, Marcel¹ 

[1] CNRS, LPMM, UMR Arts & Metiers ParisTech 7554, F-57078 Metz 3, France

[2] Nancy Univ, CNRS, LEMTA, UMR 7563, F-54500 Vandoeuvre Les Nancy, France

[3] ArcelorMittal Maizieres, R&D Automot Prod, F-57283 Maizieres Les Metz, France

关键词: Micromechanical model;    Crystal plasticity;    Intragranular substructure;    Dislocations;    Changing strain paths;    Stress-strain behavior;   

DOI  :  10.1016/j.msea.2009.03.074

来源: Elsevier

【 摘 要 】

Sheet metal forming processes are commonly associated with strain-path changes in the material. Macroscopic softening/hardening transient effects can appear due to the plastic anisotropy induced by these deformation stages. Such characteristic effects can mainly be ascribed to the intragranular microstructure development and its evolution. It subsequently becomes necessary to accurately describe the dislocation patterning during monotonic and sequential loading paths in order to obtain a relevant constitutive model. In the present work, three types of local dislocation densities are taken to represent the spatially heterogeneous distributions of dislocations inside the grain. The resulting large strain single crystal constitutive law, based on crystal plasticity, is incorporated into a self-consistent scale-transition scheme. With the hell) of a rate-independent regularization technique, this new extended multiscale model is able to calculate plastic slip activity for each grain, and it can also characterize the evolution of the dislocation microstructure. We show that our model successfully reproduces several mechanisms of intragranular substructure development that have been observed in TEM micrographs in the context of various loading conditions. Our approach is also capable of quantitatively predicting the macroscopic behavior of both single-phase and dual-phase polycrystalline steels in the context of changing strain paths. (C) 2009 Elsevier B.V. All rights reserved.

【 授权许可】

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