| Resonant Ultrasound Spectroscopy (RUS) has been applied to three systems in condensed matter physics: the C15 Laves-phase compound, TaV2H(D) x; quasicrystalline materials; and polycrystalline brass alloys.; The elastic moduli and ultrasonic loss of TaV2H(D)x were measured over a temperature range of 2.8–345 K, for a series of hydrogen concentrations 0.00 ≤ x ≤ 0.53. Parameters of the H(D) motion were derived, including activation energies, attempt frequencies and relaxation strengths. The magnitude of the effects depended linearly on x implying that relaxation of isolated H atoms caused the mechanical damping, providing a clear demonstration of the Snoek effect in an intermetallic hydride. Strong isotope effects of the H(D) motion were observed at low temperatures. The results indicated a rapid quantum-mechanical localized motion of H(D) atoms.; The shear modulus G(T) was highly dependent on x. G(T) of TaV 2 anomalously increased with increasing temperature from 3–350 K. The effect of adding hydrogen was to systematically increase the magnitude of G(T) and to reverse the temperature dependence for x ≥ 0.17. The results were described with a hydrogen-related electronic band structure model.; The elastic moduli of a Ti-Zr-Ni based icosahedral quasicrystal (QC) and a crystal approximant were derived from 15–345 K. The moduli of the QC and the approximant phases were almost the same, providing further confirmation of the similarity of the QC and approximant phases. Both phases absorb hydrogen in solid solution up to H concentrations of x ≤ 1.7. Measurements of the ultrasonic loss for the QC and approximant phases with x = 0.79 and 0.20 respectively indicated that the H motion in the QC was at least one order of magnitude faster than that of the approximant.; RUS was used to measure the elastic moduli of rolled sheets of copper and brass. The orientation distribution coefficients related to texture were determined from the elastic constants. The values were in good agreement with those obtained from neutron diffraction, as evidenced by the remarkable similarity of the ultrasonic and neutron pole-figures, supporting the idea that acoustic techniques may be used to characterize texture in rolled plates. |
