In Situ Spatial Deconvolution of Concurrent Chemical Oxidation and Localized Structural Reorganization in Copper via Laboratory Full-Field X-ray Diffraction

Laboratory full-field X-ray diffraction (FFXRD) was used to follow phase-selective structural evolution in Cu during heating at 300 °C. A dual-mode strategy yielded corrected sample-space fwhm values of 11.9 ± 3.7 μm horizontally and 17.6 ± 2.7 μm vertically at θ = 3° in the high-spatial-resolution mode, while in situ sequences used 300 s exposures at 5 min intervals. Independent measurements of Cu(111), Cu2O(111), and CuO(111) distinguished macroscopically distributed oxide-phase signals from localized Cu(111) features. Cu2O(111) intensity increased rapidly and approached a plateau, whereas CuO(111) intensity showed a delayed, approximately linear increase; these intensities are not direct measures of oxide thickness. Localized Cu(111) features appeared by the first 5 min frame in both sealed air and continuously pumped vacuum below 10 Pa, indicating that an air atmosphere was not required for their onset within the temporal resolution. Because fixed-reflection intensity changes are not unique evidence of recrystallization, these features are interpreted as localized structural reorganization consistent with recrystallization and/or grain growth. Grazing-incidence measurements provided overlapping depth-weighted sensitivity rather than discrete layer resolution. Laboratory FFXRD therefore provides an accessible complement to synchrotron methods for long-duration, phase-selective mapping of heterogeneous structural evolution.