<Abstract>

The results of experiments on bicrystals with various grain boundaries moving under mechanical stress will be reviewed. The boundary migration – shear coupling will be discussed. The extended geometric model of boundary migration - shear coupling for evaluating the coupling factor, i.e. the amount of produced shear, for twin and grain boundaries in various crystal structures will be presented. It will be shown that the coupling factors calculated according to the proposed general formula are in excellent agreement with respective experimental and simulation data known from literature. Also, the results of experiments with specifically oriented magnesium single crystals deformed at ambient and elevated temperatures in channel-die plane strain compression will be reported. The formation of anomalous{10-12} extension twins, which had negative Schmid factors and produced a strain opposite to the imposed deformation will beanalyzed considering the operating deformation mechanisms and heterogeneities with respect to lattice rotation.

Prof. Sadahiro Tsurekawa FAST, Kumamoto University	Prof. Dmitori Molodov Institute of Physical Metallurgy and Metal Physics, RWTH Aachen University, Germany IROAST Visiting Professor

54th IROAST Seminar