Phase identification in a U - Zr/Ni - Cr diffusion couple using synchrotron radiation

The diffusion zone between a U-23 at. % Zr alloy and a Ni-16.4 at. % Cr alloy exhibited nine distinct phase layers, many of which were mixtures of two phases. Four single-phase regions were less than 10 μm wide. To identify these phases by diffractometry, a synchrotron x-ray beam was collimated by a 50 μm by 1 mm slit. This beam was translated across the sample to obtain diffraction patterns throughout the diffusion zone. In this way, only a few phases were simultaneously within the beam, easing identification of the phases. Strains in the lattice due to solid solution were also observed. These microdiffraction techniques are applicable to a wide range of material systems.