X-ray diffraction line broadening due to dislocations in non-cubic crystalline materials. III. Experimental results for plastically deformed zirconium

Procedures of X-ray diffraction line profile analysis for the evaluation of the dislocation content in plastically deformed hexagonal materials were tested by means of conventional powder diffractometry on polycrystalline zirconium deformed under tension at 77 K. In order to obtain a representative picture of the dislocation-induced X-ray line broadening a series of reflections was measured. The integral breadths and the Fourier coefficients were evaluated by both direct profile-shape analysis and profile fitting with analytical functions. The results show a significant anisotropy of the line broadening. The 0001 reflections are clearly less broadened than most of the others. According to the theoretical calculations presented previously such a phenomenon can be expected if the plastic deformation favours generation of dislocations with Burgers vectors a/3 〈2{\bar 1} {\bar 1}0〉.