|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||High Entropy Alloys VI
||Percolation Effects in Atomic Transport due to Vacancy Diffusion in Random Binary Alloys
||Yury Osetskiy, Laurent Béland, Alexander Barashev, Yanwen Zhang
|On-Site Speaker (Planned)
Microsecond scale molecular dynamics (MD) simulations of vacancy diffusion in fcc Ni-Fe random alloys has shown that percolation effects are responsible for a specific composition dependence of the tracer diffusion coefficient that is a well pronounced minimum of the tracer diffusion coefficient near ~20 at.%Fe that is around the site percolation threshold in the fcc crystal lattice. The MD results are reproduced by on-the-fly kinetic Monte Carlo (kMC) modeling based on the activation-relaxation technique. It is shown that the activation energy of vacancy-atom exchange jumps is a function of composition and has a maximum at ~20at.%Fe. This results in a minimum of the tracer diffusion coefficient, which is more pronounced at lower temperatures, as observed in MD modeling. A fast method for preselecting materials with a desired properties for experimental examination, based on using kMC with composition-dependent jump barriers obtained from first principles, is suggested.
||Planned: Supplemental Proceedings volume