La extinción primaria y el factor estático de Debye-Waller en la caracterización de níquel con textura mediante difracción de rayos X

Abstract

The texture analysis using X-ray diffraction (XRD) implies measurement of pole figures (PFs) from the diffracted intensities considering the model of kinematical dispersion. The extinction phenomenon results in a decrease of diffracted intensity and that in turn in a decrease of pole densities (PDs). The phenomenon appears in the kinematical theory of XRD as the primary extinction and the secondary extinction to characterize the loss of intensity of kinematical dispersion. In turn, the static Debye-Waller factor is an integral characteristic of defects in crystals that is introduced in the kinematical theory of XRD and also is used in dynamical theory of XRD. In this work the correlation between the primary extinction coefficient and the static Debye-Waller factor in the case of textured nickel was determined. The value of static Debye-Waller factor was determined from the value of the calculated primary extinction coefficient. For the evaluation there were used PDs in the maxima of PFs obtained for 111 and 200 reflections with MoK$\alpha$ radiation, and the PDs in the maxima of PFs obtained for the first and second orders of these reflections with Cu K$\alpha$ and Co K$\alpha$ radiations. There were calculated the dislocation densities in grains using values of static Debye-Waller factor and the extinction coefficients. The dislocation densities calculated from these two characteristics are practically equal.