The kinetics of the ordering and coarsening of B2-ordered domains is studied using atomistic kinetic Monte Carlo simulations. Special emphasis is put on the effect of annealing temperature, alloy composition, and atom dynamics on the coarsening behavior. When atomic diffusion proceeds by vacancy jumps to nearest-neighbor sites, a transient slow coarsening regime is observed at temperatures below half the order-disorder transition temperature Tc. It results in apparent coarsening exponents that decrease with decreasing the annealing temperature. Values as low as 0.14 are measured at 0.25Tc. Slow transients take place in both stoichiometric and nonstoichiometric alloys. These regimes are correlated with the transient creation of excess antisites during domain disappearance. Since antiphase boundary mobility decreases with increasing antisite concentration, this transient excess results in the slow coarsening observed in simulations.
|Original language||English (US)|
|Number of pages||11|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Jan 1 2000|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics