The diffraction of X-rays by close-packed crystals containing both `growth stacking faults' and `deformation or transformation stacking faults'

Abstract

The general theory is developed of the X-ray diffraction effects exhibited by (a) different close- packed structures (h,k, hk, hkk, hhk, hhkk types) containing 'growth stacking faults', assuming a four-layer influence; (b) hexagonal and close-packed cubic crystals in which 'growth stacking faults' and 'deformation or transformation stacking faults' coexist; and (c) hk-- and hkk-crystals (SiC-4H and SiC-6H types) containing 'deformation stacking faults'. The manner in which a 'fault' of the first or second type disturbs the regular sequences of the layers is stated in a general way. Expressions are derived for the reciprocal-space intensity dis- tribution as a function of the parameters (four, two, one, one in the different cases) which describe the densities of the faults. It is shown how these parameters can be determined from measurements of the X-ray intensities or the displacements of the peaks of the diffuse reflexions.