Berlin 2008 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 23: Poster session

MM 23.27: Poster

Tuesday, February 26, 2008, 14:45–18:00, Poster B

Introduction of Slip System Resolved Statistical Work Hardening Model — •Denis Novokshanov and Volker Mohles — Institute of Physical Metallurgy and Metal Physics, RWTH Aachen Kopernikusstr. 14, D-52074 Aachen, Germany

A slip system resolved statistical work hardening model for single crystals has been developed. It is based on the dislocation density-based work hardening model 3IVM+, which in turn is an improved version of the 3IVM (three internal variables model) [1]. 3IVM+ predicts stress-strain curves for large ranges of temperature and strain rate. In the new model, the microstructure evolution of 3IVM+, i.e. the dislocation density evolution, is left unchanged. But the kinetic equation of state of 3IVM+ has been inverted: the new model considers the glide velocity of dislocations as a function of temperature and the external applied stress. This allows to consider each glide system individually by applying the corresponding Schmid factor in the stress projection. Hence all slip systems contribute to the overall deformation according to their intrinsic kinetics, which is defined by the crystal's orientation and the load axis. This leads tho realistic stress-strain curves and orientation changes for a single crystal. The model can be used as a replacement for 3IVM(+) in engineering applications of FEM. For polycrystals, the interaction between grains can be introduced in future by elastic stresses caused by differing rotations of adjacent grains.

1. F. Roters, D. Raabe, G. Gottstein, Acta Materiallia 48 (2000) 4181-4189