The effect of nonhydrostaticity on measuring the pressure in metals by energy dispersive X-ray diffraction in the diamond anvil cell

Abstract

Using the Chua-Ruoff scaling relation for the pressure dependence of the compressive flow stress, the effect of the presence of a finite yield strength on the measurement of pressure in a diamond anvil cell by energy dispersive X-ray diffraction is calculated. In experiments in which the pressure was found by X-ray diffraction to be 364 GPa (exceeding the pressure at the center of the earth) without this correction, it is calculated that the actual pressure lies in the range 378-395 GPa with the correction for nonhydrostaticity being 5-9%.