The effect of low-temperature structural relaxation on free volume and chemical short-range ordering in a Au 49 Cu 26.9 Si 16.3 Ag 5.5 Pd 2.3 bulk metallic glass

Structural changes due to low-temperature relaxation in a Au49Cu26.9Si16.3Ag5.5Pd2.3 bulk metallic glass are investigated with a combination of positron annihilation lifetime spectroscopy (PALS) and high-intensity synchrotron X-ray scattering. The free volume content of the glass remains unaffected during annealing at 50 degrees C while distinct changes in the chemical short-range order occur on a nearest-neighbor length scale of similar to 3 angstrom. A highly localized process of atomic rearrangement is envisioned, which may help to understand the microscopic origin of the beta-relaxation. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.