Anomalous Small-Angle X-Ray Scattering Characterization of Model Pressure Vessel Alloy Microstructures

Anomalous small-angle x-ray scattering (ASAXS) experiments were performed at energies near the Mn-K and Fe-K absorption edges on an Fe-0.9 Cu wt.%-1.0 Mn wt.% alloy subjected to either annealing at 450°C, 24 hrs or irradiation with 10 MeV electrons to 0.5 mdpa at 300°C. A Guinier analysis of the net scattered intensity revealed scatterers with radii of 16.5.16.8 Å and 16.4.17.3 Å for the irradiated and annealed foils, respectively. The variation in net scattered intensity with photon energy in the annealed sample was consistent with scattering contrast variations expected for Cu-rich, Cu-Mn precipitates. Minimal variation in net intensity (scattering contrast) with energy determined that Cu-Mn precipitates were not detected in the irradiated sample.