Configuration of dislocations in low-angle kink boundaries formed in a single crystalline long-period stacking ordered Mg-Zn-Y alloy
Abstract
The dislocation configuration around low-angle kink boundaries formed in bent single crystalline long-period stacking ordered (LPSO) Mg85Zn6Y9 alloys was investigated. Intragranular misorientation axis (IGMA) analysis through SEM/EBSD observation and g•b analysis through TEM observation were conducted. Various kink bands possessing different lattice rotation axes ranging from < 1 1 bar 00 > to < 1 2 bar 10 >, i.e. along < 1 1 bar 00 >, <uvt0>, and < 1 2 bar 10 > were revealed using IGMA analysis. TEM observation with g•b analysis unveiled that the < 1 1 bar 00 >-rotation kink boundary observed using IGMA analysis consisted of basal <a> edge dislocations with one Burgers vector, while the < 1 2 bar 10 >/<uvt0>-rotation kink boundaries were comprised of basal <a> edge dislocations with more than one Burgers vector. Low-angle kink boundaries were regarded as low-angle tilt boundaries consisting of perfect basal <a> dislocations, regardless of their rotation axes. The formation of various kink bands with <uvt0>-combination-rotation axes ranging from < 1 1 bar 00 > to < 1 2 bar 10 > suggests that the statistically stored basal <a> dislocations may turn into geometrically necessary basal <a> edge dislocations during the initial stage of low-angle kink boundary formation. When a kink boundary is considered as a disclination, IGMA analysis capable of determining the lattice rotation axis and the angle is effective in evaluating the Frank vector of the kink boundary.
- Publication:
-
Acta Materialia
- Pub Date:
- June 2018
- DOI:
- 10.1016/j.actamat.2018.03.034
- Bibcode:
- 2018AcMat.151..112M
- Keywords:
-
- Magnesium;
- Long-period stacking ordered structure;
- Kink deformation;
- Dislocation