Preferred crystallite orientations depth profile in the two phase alloy Zn-22% wt Al, determined by X-ray and neutron diffraction

In order to observe the texture inhomogeneity of the Zn-22% wt Al alloy, polar figures for the β-phase (111) and β-phase (002) reflections were measured by X-ray diffraction at four different depths in a hot rolled sheet sample. Also a sample in the form of a cube was assembled with several pieces of the sheet, with the same degree of deformation, to make it suitable for the measurement of its polar figures by means of neutron diffraction. In both phases, the corresponding typical rolling texture was observed. Therefore, it does not seem to exist any strong correlation between preferred orientations in both phases, as it might be expected. β-phase polar figures show a homogeneous texture, with a very small increasing orientation dispersion related to depth. The α-phase polar figures are very weak and they vary statistically but retaining the main characteristics of hot rolling polar figures. Neutron diffraction polar figures were also obtained and the results are in good agreement with the X-ray polar figures. Probably, easy grain boundary sliding, which is one of the main mechanisms of superplasticity in this alloy, is also responsible for a homogeneous distribution of strain and stress in the bulk of the sample.