Low temperature dependence of elastic parameters and internal frictions for glassy alloy Cu(45)Zr(45)Al(5)Ag(5)

Using ultrasonics, acoustic characteristics of a glassy alloy Cu(45)Zr(45)Al(5)Ag(5) are examined in order to understand its low-temperature elasticity. Longitudinal and transverse wave velocities, eight kinds of elastic parameters, and dilational and shear internal frictions were simultaneously measured as a function of temperature between 77 and 373 K in Cu(45)Zr(45)Al(5)Ag(5) alloy, using an ultrasonic pulse method. The inflection at around 328 K for the anisotropy factor, the four elastic moduli, the Poisson ratio, the Debye temperature, and the 295 K peak of dilational friction show one topological change (pseudo-transition) associated with electron-phonon coupling, accompanied by accumulation of strain. A monotonic decrease from 77 K in Young and shear moduli and the Debye temperature as well as a pronounced increase from 150 K in shear friction indicates thermal relaxation of squeezed free-volume, accompanied by an increase in atomic distance and uniaxial volume-preserving deformation. (c) 2008 American Institute of Physics.