Grain boundary kinetics in magnesium alloys from first principles
Mahjoub, Reza 1Ferry, Michael 2Stanford, Nikki1
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作者信息
1. Univ South Australia
2. Univ New South Wales UNSW Sydney
折叠
Abstract
Grain boundary migration in magnesium alloys has been studied using quantum mechanical calculations implementing the nudged elastic band method. Four crystallographically different boundaries were examined: two twin boundaries and two general grain boundaries that showed no crystallographic symmetry across the boundary plane. The activation energies for boundary migration were determined from the minimum energy pathways, and these energies were consistent with experimental values. It was found that the activation energy is linearly related to the coordination number of the boundaries. This indicates that boundaries with lower coordination numbers showed smaller activation energies and thus higher mobilities than the more orderly boundaries with larger coordination number and larger activation energies. The effect of solutes at the boundary was also studied, and it was found that most solutes with low co-ordination number decreased the activation energy for boundary migration, but the effect of solutes on boundaries with high coordination number was strongly dependent on the solute chemistry.
Key words
Kinetics/Grain boundary: first principles/Electronic structure/CINEB/PLANE-WAVE/MOLECULAR-DYNAMICS/GROWTH KINETICS/MIGRATION/MOBILITY/SEGREGATION/DISLOCATION/SIMULATION/INTERFACE/COHP
NSTL
Elsevier