HARMONIC BEHAVIOR OF METALLIC GLASSES UP TO THE METASTABLE MELT

In two amorphous alloys ZrTiCuNiBe and ZrAlNiCu coherent neutron scatt ering has been measured over five decades in energy, including measure ments in the metastable melt of a metallic alloy more than 80 K above T-g. In the vibrational spectra a pronounced ''boson'' peak is found: Even in crystallized samples the density of states exceeds the Debye o mega(2) model, and in the amorphous state low-frequency vibrations are further enhanced. The peak position shows no dispersion in q, while i ntensities are strongly correlated with the static structure factor. O ver the full energy range the temperature dependence is strictly harmo nic. From high-energy resolution measurements we establish lower bound s for the temperatures at which structural alpha and fast beta relaxat ion become observable.