Abstract
From strain-rate- and temperature-dependent deformation studies on nanocrystalline PdAu alloys with grain sizes 10 nm, the shear activation volume (6 ), strain-rate sensitivity (), as well as the Helmholtz (0.9 eV) and Gibbs free energy of activation ( eV) have been extracted. The close similarity to values found for metallic glasses indicates that grain boundary mediated shear shuffling dominates plasticity at the low end of the nanoscale. More fundamentally, we find that the energy barrier height exhibits universal scaling behavior , where is a residual load, giving rise to a generalization of the Johnson-Samwer scaling law of yielding in metallic glasses.
- Received 25 June 2013
- Revised 31 March 2014
DOI:https://doi.org/10.1103/PhysRevB.89.184108
©2014 American Physical Society