Dresden 2011 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 11: Glasses I (Joint Session of DY, DF, CPP)

DF 11.3: Talk

Wednesday, March 16, 2011, 10:45–11:00, KÖN Farb

Dynamics of shear transformation zones during mechanical cycling of glassy CuTi - a molecular dynamics study — •Lennart Fricke und S. G. Mayr — Leibniz-Institut fuer Oberflaechenmodifizierung, Translationszentrum fuer regenerative Medizin und Fakultaet fuer Physik und Geowissenschaften der Universitaet Leipzig, 04318 Leipzig

Plastic deformation of bulk metallic glasses at low temperatures occurs in highly localized regions, called shear-transformation-zones (STZ) [1] - as corroborated recently in detailed experimental and simulational studies. After activation, these STZs should possess a memory of their configuration prior to transformation due to confinement by the surrounding elastic matrix, i.e. the Eshelby back-stress. While this picture surely is intuitive, it is particularly interesting whether it applies in a strict or only statistical sense and up to what strain levels. With this background we study shear behavior during mechanical cycling of CuTi with a maximum of 1% to 10% shear strains in large--scale MD simulations using realistic embedded atom method (EAM) potentials. Evaluating suitable quantities, including non-affine displacements and atomic-level Basinski--Duesbery--Taylor (BDT) stresses, we address the reversibility of STZs and the underlying physics on the atomic scale.

[1] A. S. Argon, Acta Metall. 27, 47 1979

This project is funded by the German DFG - PAK 63