Antiphase domains in plastically deformed Zn-Mg-Dy single quasicrystals

The results of microstructural investigations of plastically deformed and undeformed Zn-Mg-Dy single quasicrystals by means of transmission electron microscopy are presented. Planar defects were observed in hear-treated quenched samples and in deformed samples, which could be identified as antiphase boundaries of the face-centered icosahedral structure. A strong increase of the density of antiphase boundaries during plastic deformation was observed, which could be attributed to the movement of partial dislocations. The plane normals of the antiphase boundaries were determined for differently treated samples. In heat-treated and quenched samples 90% of the plane normals were found to be parallel to fivefold directions. In deformed samples, planes perpendicular to pseudo-twofold (1/1 2/1 1/2) directions are most frequently observed. These planes are inclined by an angle of 46 degrees with respect to the [0/0 0/0 0/2] compression direction and therefore possess a high Schmid factor.