Abstract
Atomic migration in an ordered binary alloy with B2 structure is studied by atomistic Monte Carlo simulations where atom migration results from exchanges with a single vacancy on a rigid lattice. Highly correlated vacancy sequences are observed and studied using improved residence time algorithms. Beside the classical 6-jump cycle a wide range of other correlated sequences is also identified. Furthermore, when interaction energies of the model present a high degree of asymmetry, two effects have been observed: tracer diffusion coefficient ratio can be as large as 4.5 which can be rationalized in terms of the identified sequences; diffusion coefficients exhibit an upward curvature below the order-disorder transition temperature. These two effects have been observed in some alloys such as CoGa and therefore can be qualitatively reproduced without the need to invoke a divacancy mechanism.
Original language | English (US) |
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Pages (from-to) | 297-302 |
Number of pages | 6 |
Journal | Defect and Diffusion Forum |
Volume | 143-147 |
DOIs | |
State | Published - 1997 |
Externally published | Yes |
Keywords
- B2 phase
- Monte-carlo simulations
- Non-arrhenian behaviour
- Vacancy cycles
ASJC Scopus subject areas
- Metals and Alloys