Extended zonal dislocations mediating ? twinning in titanium
Abstract
Using molecular dynamics (MD) simulations, the ? twinning mechanism in titanium (Ti) was studied by analyzing the interfacial structure at the twin boundary (TB). The simulation results reveal interesting twin growth controlled by interfacial dislocations at the TB. The elementary twinning dislocations (bT ) nucleate and glide in pairs but separately and sequentially on two neighboring planes, significantly different from conventional zonal dislocations, which spread over two or more twinning planes with each plane comprising one Burgers vector of an elementary twinning dislocation. The twin growth can be approximately described as ? These two separate elementary twinning dislocations amount to a net Burgers vector 2bT ≈ 0.16 nm along the twinning vector ? , with the components in the in-plane direction perpendicular to η 1 canceled out. These results support the classical twinning theory in which a homogeneous shear and local shuffling have to be involved. A mechanism taking into consideration local structure of the twinning plane for such extended zonal dislocations is discussed.
- Publication:
-
Philosophical Magazine
- Pub Date:
- March 2012
- DOI:
- 10.1080/14786435.2011.637985
- Bibcode:
- 2012PMag...92.1006L
- Keywords:
-
- plastic deformation;
- twinning;
- dislocation;
- titanium