Internal friction and elastic modulus of bulk metallic glasses

The mechanical relaxation in binary, ternary, quaternary, and quitary bulk metallic glasses with widely different glass-forming ability, or the critical cooling rate, has been studied. A single-roller melt-spinning apparatus was used for preparing thin specimens. The internal friction Q⁻¹ and the oscillation frequency f of the specimens were measured using an inverted torsion pendulum with the free decay method. The measurements were performed from room temperature, through the glass transition temperature T_g, up to the crystallization temperature T_x. As the temperature is increased, the background Q⁻¹ increases, and peaks can usually be seen near T_g and T_x. The shear modulus, which is proportional to f², is changed near the Q⁻¹ peak. The experimental data are presented and overall features of the results are discussed.