Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8163744 | Physica B: Condensed Matter | 2013 | 5 Pages |
Abstract
Dislocations in BCC metals are of crucial importance for understanding behavior of fusion materials. In this study model positron lifetime quantum-mechanical calculations have been carried out in the two-component density functional theory (DFT) in local density approximation (LDA) for perfect iron and tungsten lattices, lattices with ã1Â 0Â 0ã edge and 1/2ã1Â 1Â 1ã screw dislocations and several cases in which dislocations interact with a vacancy, bi-vacancy and vacancies containing hydrogen or helium atoms. The core structures of the dislocations have been obtained by MD-simulations using Mendelev and Ackland potentials for iron and Finnis-Sinclair potential for tungsten. The calculated values for iron are 153Â ps for edge dislocation and 124Â ps for screw dislocation, while for tungsten are 161 and 130Â ps, respectively. We report new results for screw dislocation showing that minor dilation of the lattice volume associated with second-order elasticity theory influences the calculated positron lifetime.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
P. Staikov, N. Djourelov,