A method of separation of double Bragg scattering from small-angle scattering of X-rays by metals and alloys

Small-angle scattering of X-rays from polycrystalline assemblages of metals, alloys and other crystalline materials can be due to double or multiple Bragg scattering in addition to the 'true' small-angle scattering. Separating these two components of small-angle scattering (SAS) is a necessary requirement for proper interpretation of SAS data. This has been achieved in this work by considering the polarization ratio of X-rays scattered by polycrystalline assemblages. The proportion of 'true' SAS has been expressed as a function of the total diffracted intensity and the polarization ratio. Application to polycrystalline assemblages of aluminium and several Cu-Al alloys shows that the proportion of double Bragg reflection (DBR) is small compared to that of 'true' SAS.