FEM-simulation of the hardening behavior of FCC single crystals

Abstract

Although the deformation behaviour of single crystals has been investigated experimentally and theoretically for several decades, a generally accepted theory for the underlying hardening processes has not been found yet. In the last years, computer simulations offered additional investigation possibilities, whereby especially the use of constitutive equations in combination with the finite element method has delivered important results. The publication reports on an FEM crystal plasticity model-which was previously used for multicrystals-and its application to single crystals. The model is designed for the low temperature behaviour of pure fcc metal crystals. The rate dependent equations include kinematic and isotropic hardening, with formulations founded on the responsible slip system processes. The obtained simulation results coincide very well with typical single crystal experiments like tensile or latent hardening tests, which confirms the chosen mathematical approaches. It is shown that both kinematic and isotropic processes determine hardening, whereby the underlying slip system interactions play an important role. Moreover, experimentally not visible processes can be studied in detail and are discussed concerning the metal physics theories, which finally contributes to a better understanding of metal deformation behaviour.