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 Tg, up to the crystallization temperature Tx. As the temperature is increased, the background Q−1 increases, and peaks can usually be seen near Tg and Tx. 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.