A dislocation-density-based 3D crystal plasticity model for pure aluminum Alankar Alankar * , Ioannis N. Mastorakos, David P. Field School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920, USA Received 9 June 2009; received in revised form 10 August 2009; accepted 11 August 2009 Available online 8 September 2009 Abstract A dislocation-density-based crystal plasticity finite-element model (CPFEM) is developed in which different dislocation densities evolve. Based upon the kinematics of crystal deformation and dislocation interaction laws, dislocation generation and annihilation are modeled. The CPFEM model is calibrated for pure aluminum using experimental stress–strain curves of pure aluminum single crystal from the literature. Crystallographic texture predictions in plane-strain compression of aluminum are validated against experimental observations in the literature. The framework is implemented in ABAQUS with user interface UMAT subroutine. Ó 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Keywords: Dislocation; Crystal plasticity; Aluminum; Crystallographic texture; Rolling 1. Introduction Crystal plasticity models using the finite element method (FEM) have proved useful for studying texture evolution in plastic deformation of metals, e.g. rolling, extrusion, etc. [1]. For correct prediction of local texture and grain bound- ary structure, interaction of constituent grains should be considered [2–5]. However, single crystal models form the basis of polycrystalline models and are used for studies of plastic anisotropy and texture evolution in metal deforma- tion. In a polycrystalline material, each crystallite deforms according to its individual orientation and the local ther- momechanical conditions imposed on it, e.g. deformation gradient, strain rate, temperature, tractions, etc., in the polycrystalline aggregate. Since the introduction of dislocations as “plasticity car- riers” by Taylor in 1934 [6], there have been many advances in the understanding of physics of dislocations, which has enabled the modeling of crystal plasticity. Major contribu- tions on dislocation theories of work hardening are due to Seeger and Schoeck [7], Nabarro et al. [8], Cottrell and Stokes [9], Kulhmann-Wilsford [10,11], Kocks [12], Mec- king and Kocks [13], Estrin and Mecking [14], Kocks et al. [15], Gottstein and Argon [16] and Nabarro [17].A pioneering review of the strain hardening in face-centered cubic (fcc) metals can be found in the work of Kocks and Mecking [18]. Classical formulations of single crystal plasticity come from the contributions of Hill [19], Hill and Rice [20], Asaro and Rice [21], Peirce et al. [22], and Hill and Hav- ner [23]. A detailed review of the aforementioned approaches is presented by Asaro [24]. A wide variety of currently available crystal plasticity models using finite element methods (CPFEM) can be classified into two major types. In the first type, slip resistances are used as internal state variables (e.g. [1,21,25–27]). In the sec- ond, dislocation density/densities are used as internal state variables (e.g. [4,28–37]). The major difference between the two is that the latter involves evolution of dislocation densities explicitly in the framework of the model. While all the dislocation-density-based models are based on the scale of slip systems, they can be clas- sified in different categories based on the way dislocation 1359-6454/$36.00 Ó 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.actamat.2009.08.028 * Corresponding author. Tel.: +1 509 205 0537; fax: +1 509 335 4662. E-mail address: alankar.alankar@email.wsu.edu (A. Alankar). www.elsevier.com/locate/actamat Available online at www.sciencedirect.com Acta Materialia 57 (2009) 5936–5946