Structural relaxation in a heavily cold-worked metallic glass

Differential scanning calorimetry heating runs on as-cast and shot-peened bulk metallic glass Pd40Cu30Ni10P20 show a broad temperature range of heat release (relaxation spectrum) with two peaks. The higher-temperature peak is reduced by shot-peening, suggesting uniform deformation and partial relaxation of the glassy structure. Peening of pre-annealed samples shows the stored energy of cold work to be a few per cent of the work done. Peening increases atomic mobility, revealed by a downward temperature shift of the relaxation spectrum.