Synchrotron Radiation Study of Second-Phase Particles and Alloying Elements in Zirconium Alloys

We have conducted a study of second phase particles and matrix alloying element concentrations in zirconium alloys using synchrotron radiation from the Advanced Photon Source (APS) at Argonne National Laboratory. The high flux of synchrotron radiation delivered at the 2BM beamline, compared to conventional X-ray generators, enables the detection of very small precipitate volume fractions. We detected the standard C14 hep Zr(Cr,Fe)₂ precipitates (the stable second phase in Zircaloy-4) in the bulk material at a cumulative annealing parameter as low as 10^-20 h, and we followed the kinetics of precipitation and growth as a function of the cumulative annealing parameter (CAP) in the range 10^-22 (quench) to 10^-16 h. In addition, the unique combination of spatial resolution and elemental sensitivity of the 2ID-D/E microbeam line at the Advanced Photon Source at Argonne (APS) allows study of the alloying element concentrations at ppm levels in an area as small as 0.2 X 0.3 μm. We used X-ray fluorescence induced by this sub-micron X-ray beam to determine the concentration of these alloying elements in the matrix as a function of alloy type and thermal history. We discuss these results and the potential of synchrotron radiation-based techniques for studying zirconium alloys.