Low frequency internal friction investigation of microstructural transition in Nd60Al10Fe20Co10 bulk metallic glass upon continuous heating

The low frequency internal friction and the shear modulus of a bulk metallic glass Nd60Al10Fe20Co10 have been measured with a inversed torsional pendulum at about 0.2similar to8 Hz over a temperature range from room temperature to 790 K. The crystallization kinetics of the alloy was studied by calorimetric method and the structure of the samples was determined by X-ray diffraction. It is shown that upon continuous heating, three damping peaks are observed at 536 K, 698 K and 770 K, respectively, which are attributed to three kinds of structural relaxation processes. The results obtained are explained in terms of the structural rearrangement, mainly topological ordering, formation of metastable phases and crystallization processes. The activation energies for the relaxation processes have been estimated from the shift of the internal friction peaks by the frequency change.