Molecular dynamics simulation of aluminium diffusion in decagonal quasicrystals

Aluminium diffusion in decagonal Al-Ni-Co and Al-Cu-Co quasicrystals is investigated by molecular dynamics simulations. Results obtained with newly developed EAM potentials are compared to previous work with effective pair potentials [Phys. Rev. Lett. 93, 075901 (2004)]. With both types of potential, strong aluminium diffusion is observed above two thirds of the melting temperature, and the general behaviour of the system is quite similar. The diffusion constant is measured as a function of temperature and pressure, and the activation enthalpies and activation volumes are determined from the resulting Arrhenius plot. For a number of important diffusion processes, the energy barriers are determined with molecular statics simulations. The qualitative behaviour of the dynamics is also confirmed by ab-initio simulations.