Using Cu-Zr models, we demonstrate icosahedral ordering as a microscopic origin of the non-Arrhenius dynamical slowing down in metallic supercooled liquids. This correlation between the structural and dynamical heterogeneities underlies the evolution of the energy barrier for relaxation upon undercooling, as well as the eventual glass transition that leads to the formation of bulk metallic glasses (MGs). Our analysis of the energy barrier to plastic relaxation in MGs relates their macroscopic strength and plasticity to the local structures developed in the MGs. The structure-dynamics perspective explains not only the composition-dependent mechanical properties but also the known correlation between the strength of MGs and the glass transition temperature.

• Received 23 June 2008

DOI:https://doi.org/10.1103/PhysRevB.78.014207