## 5aPA1. Temperature variation of elasticity of (alpha)-quartz by the rectangular parallelepiped resonance method.

### Session: Friday Morning, May 17

### Time: 8:10

**Author: Ichiro Ohno**

**Location: Dept. of Earth Sciences, Ehime Univ., Bunkyou-cho 2-5, Matsuyama, 790-77 Japan**

**Abstract:**

The resonant ultrasound spectroscopy of a specimen of (alpha)-quartz single
crystal was carried out up to 558 (degrees)C, just below the (alpha)--(beta)
transition (T[inf 0]=573 (degrees)C), and all of the independent elastic
constants were determined simultaneously by the rectangular parallelepiped
resonance method. The results show that bulk moduli decrease largely toward
T[inf 0], while the shear moduli show only slight decreases. The constant, C[inf
14], characteristic of trigonal crystals, decreases to just below T[inf 0], but
it seems not to vanish, but to remain a finite value, even at T[inf 0]. It is
noted that the isotropic aggregate of (alpha)-quartz is a curious and scarce
material, in the sense that its bulk modulus is smaller than the shear modulus,
and Poisson's ratio is very small or even negative at temperatures higher than
450 (degrees)C. The effect of piezoelectricity of (alpha)-quartz on the
theoretical frequencies was investigated in order to know whether the ordinary
nonpiezoelectric theory gives considerably inaccurate resonance frequencies. It
was shown that the nonpiezoelectric theory gives a frequency lower than the
frequency given by piezoelectric theory, but the difference is 0.5% at most.

from ASA 131st Meeting, Indianapolis, May 1996