Low-temperature dependence of elastic moduli and internal friction for glassy Pd_42.5Ni_7.5Cu₃₀P₂₀

Abstract

Longitudinal and transverse wave velocities, eight kinds of elastic parameters, and the dilational and shear internal friction of Pd_42.5Cu₃₀Ni_7.5P₂₀ glassy alloy have been simultaneously measured as a function of temperature in the range from 77 to 373 K, using an ultrasonic pulse method. Monotonic decreases in the Young and shear moduli and in the Debye temperature in the range above 77 K are interpreted in terms of thermal relaxation of squeezed free volumes, accompanied by an increase in the interatomic distances, the appearance of entropy elasticity, and a uniaxial volume-preserving deformation. A 272-K valley of dilational friction seems to correspond to a topological change associated with electron–phonon coupling caused by the release of strains.

Keywords:

• glassy alloy
• low temperature
• elastic modulus
• elasticity
• internal friction
• metallic glasses
• ultrasonics

Acknowledgments

This work was supported by a Grant-In-Aid for Science Research in a priority Area’Research and Development Project on Advanced Metallic Glasses, Inorganic Materials and Joining Technology’ from the Ministry of Education, Science, Sports and Culture, Japan, and by the JSPS Asian CORE Program.