Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 30: Topical Session: Fundamentals of Fracture - Modelling Intergranular Fracture

MM 30.5: Vortrag

Mittwoch, 13. März 2013, 11:15–11:30, H4

A high-resolution look at crack tip deformation — •Christoph Kords¹, Philip Eisenlohr¹, Arshad Tahir², Rebecca Janisch², and Franz Roters¹ — ¹Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany — ²ICAMS, Ruhr-University Bochum, 44780 Bochum, Germany

The deformation behavior around a pre-existing intergranular crack is simulated in a two-dimensional setting for a grain boundary in bcc Mo. The associated boundary value problem is solved at very high spatial resolution (millions of pixels) by means of a recently implemented spectral method based on fast Fourier transforms. The cohesive properties of the grain boundary are derived from ab-inito density functional theory calculations. Our interest focuses on the conditions under which the theoretical interface strength obtained from such atomistic calculations will be locally reached in the mesoscale simulation when dislocation-mediated crack tip plasticity is included. In this study we will investigate the influence of spatial resolution on the one hand and of the physical rigorousness of the crystal plasticity description on the other hand. To the latter end, three different crystal plasticity models are to be compared: a frequently employed (standard) power-law dislocation kinetics coupled with a phenomenological hardening description; a dislocation mechanics-based description considering dislocation densities and their reactions; and finally the same (second) model but with additional integration of the dislocation transport that is always associated with plasticity.