Allgemeines Physikalisches Kolloquium im Wintersemester 2008/2009

Ort:    48149 Münster, Wilhelm-Klemm-Str. 10, IG I, HS 2,
Zeit:    Donnerstag, 13.11.2008 16:00 Uhr c.t.
Kolloquiums-Kaffee ab 15:45 Uhr vor dem Hörsaal

Mechanik der Vielkristalle / Mechanics of Polycrystals

Prof. Dr. D. Raabe, Max-Planck-Institut für Eisenforschung, Düsseldorf

The talk presents basic research on mechanical properties of crystalline materials. Microstructure evolves in crystalline matter primarily through phase transformations and elasto-plastic deformation. This talk will focus on the latter aspect.
In order to elucidate specific plasticity mechanisms and microstructure development, we use a combination of advanced characterization, model experiments, and theoretical models at different length scales. A close integration of theory and experiment is an important feature of our approach. Most of the microstructure models that are developed in our group are formulated as continuum–based rate formulations of lattice defect kinetics and corresponding kinetic equations of state. Increasingly, we also use DFT-based electronic structure calculations to develop multiscale models pertaining to the field of crystal mechanics.
The presentation will discuss applications at the microscopic scale (Fig. 1) and at the macroscopic scale. Corresponding examples will be given for biological crystals (chitin) and metallic crystals (Ti, Mg).

Fig. 1:  Experiment, analysis, and crystal plasticity simulation of bending of a copper nanowire. a): finite element simulation b): experiment: average local lattice misorientation distribution