Anomalous elastic properties of amorphous alloys suggesting a collective motion of many atoms

The Young's modulus, E(e 1 , f), was measured as a function of the strain amplitude, e t and the measurement frequency, f, at room temperature for melt-spun amorphous (a-) Pd 80 Si 20 , a-Pd 80 Ge 20 , a-Zr 60 Cu 30 Al 10 , a-Zr 60 Cu 40 and a-Cu 50 Ti 50 alloys. E(10 -6 , f) found in the vibrating reed measurements commonly shows a decrease from E 0 in the frequency range of 10 1 -10 4 Hz, and local minima near 10 2 Hz and between 10 3 and 10 4 Hz, where E 0 is the Young's modulus found in quasi-static tensile tests. It is suggested that density fluctuations exist in a-alloys, where a high density region undergoes a resonant collective motion producing the resonant anelastic strains, and the size of the high density regions shows a distribution in dimensions. E(e t , 10 2 Hz) increases with increasing e t and finally saturates at e t of 2-4 x 10 3 . It is suggested that anelastic strains resulted from the resonant collective motions of the high density regions saturate at the high value of e t .