Modification of the diamond cell for measuring strain and the strength of materials at pressures up to 300 kilobar

Abstract

A diamond anvil cell has been adapted for determination of the strain ellipsoid in a polycrystalline sample. An x-ray beam (Mo Kα) is directed through the sample perpendicular to the loading axis. Since the diamond anvils are transparent to Mo Kα radiation, a complete cone of diffraction is available from each set of crystallographic planes (hkl). These cones produce rings on a flat film placed in front reflection geometry. From the ellipticity of these rings it is possible to calculate directly the strain ellipsoid. Material strengths as a function of pressure can then be calculated.