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Dryad

Polymorphic structure of a-type screw dislocation cores in alpha-Ti

Cite this dataset

Jany, David; Rothchild, Eric; Chrzan, Daryl (2023). Polymorphic structure of a-type screw dislocation cores in alpha-Ti [Dataset]. Dryad. https://doi.org/10.5061/dryad.8cz8w9gx5

Abstract

The dislocation core structure has a significant role in determining the dominant slip plane and the magnitude of the Peierls stress for a dislocation. An important challenge when studying dislocation cores is to determine the stable and metastable core morphologies, and then relate these structures to the dynamics of the dislocations. This study introduces a method for identifying core structures that are metastable at zero temperature. Application of this method to ⟨a⟩-type screw dislocations in α-Ti (as described using an empirical potential) reveals a multitude of (meta-)stable non-planar cores. 

This dataset contains the LAMMPS files for all the (meta-)stable morphologies of screw dislocation cores in α-Ti as described by Hennig's MEAM potential identified in this study. We identified stable core configurations for an ⟨a⟩-type screw dislocation under a compressive non-Schmid stress of 0, 250, 500, 750, and 1000 MPa applied in the [1-100] direction.

README: Polymorphic Structure of a-type Screw Dislocation Cores in alpha-Ti

https://doi.org/10.5061/dryad.8cz8w9gx5

This dataset contains LAMMPS files of (meta-)stable morphologies of screw dislocation cores in α-Ti as described by Hennig's MEAM potential. It contains the stable core configurations under a compressive non-Schmid stress of 0, 250, 500, 750, and 1000 MPa applied in the [1-100] direction.
The stable core morphologies were obtained with the ESP method or with the NEB core search method.

Description of the data and file structure

Each file is named according to the core periodicity, the stress state, and the core morphology. For instance, the file 1b_sNS_500_m1 is a supercell with a m1-type core that has a 1b-periodicity with a compressive non-Schmid stress of 500 MPa applied in the [1-100] direction. The file 2b_sNS_750_coremu1 is a supercell with a mu1-type core that has a 2b-periodicity with a compressive non-Schmid stress of 750 MPa applied in the [1-100] direction.
The reference supercells (perfect crystal in the same stress state as the dislocated cells) used to build the dislocated cells are also in this dataset, named after their stress state. 1b_sNS_500_Ref is a perfect crystal under a 500 MPa compressive stress in the [1-100] direction.

Each file is in a LAMMPS data format. The number of atoms, number of atom types, periodicity vectors, and corresponding mass for the atom types first appear in that order. It is followed by 4 columns containing the ID number, the type, and the coordinates (x, y, z) of each atom.

Funding

Office of Naval Research, Award: N00014-17-1-2283

Office of Naval Research, Award: N00014-19-1-2376