COMPRESSION BEHAVIOR OF ELASTICALLY ANISOTROPIC POLYCRYSTALS USING ENERGY-DISPERSIVE X-RAY-DIFFRACTION

The compression behaviour of a foil of Cu3Au in a pressure medium of N aCl has been studied by energy-dispersive X-ray diffraction in a diamo nd-anvil cell. Evidence from stress analysis and peak broadening of th e foil (the most extreme example of a non-ideal powder) throws light o n the compression of powders under non-hydrostatic conditions. A compl ete pressure cycle, including re-pressurization after pressure release , shows that significant plastic deformation takes place which results in large deviations from a (hydrostatic) equation of state. The origi n of the deformations is traced to shear stresses transmitted to the s ample through the pressure medium.