Elastic properties of single-crystal NaCl under high pressures to 80 kbar.

Abstract

Adiabatic elastic moduli for a NaCl single-crystal under high pressures up to 80kbar at room temperature were determined through ultrasonic sound velocity measurements in a cubic anvil-type high pressure apparatus with a solid pressure transmitter. Ultrasonic measurements far both the longitudinal and transverse waves were carried out simultaneously by a pulse-echo-overlap technique. Pressures were determined by X-ray measureinents of NaCl based upon Decker's equation of state. The adiabatic bulk modulus Ks calculated from the Decker's formulae as well as various pressures was combined with the ultrasonic sound velocity to provide pressure dependence of elastic moduli Cij for NaCl. Results of measurements yield zero-pressure values of C11=5.16×1011, C12=1.22×1011 and C44=1.36×1011dynes/cm2. The plots of Cij versus pressure are fit by a least square method with straight lines for pressure range zero to 80kbar, to give the following slopes: ∂C11/∂p=8.72, ∂C12/∂p= 1.22 and ∂C44/δp=0.31. In the overlapping pressure range, ∂Cij/∂p values obtained by this work ae slightly smaller than those obtained by others.