XRD Phase Analysis and Residual Stress Evaluation of Cr–Zr-Based Coatings for Accident Tolerant Fuel Cladding

Document Type : Original Article

Authors

1 Plasma and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute (NSTRI) Atomic Energy Organization of Iran, Tehran, Iran

2 Nuclear Science and Technology Research Institute (NSTRI)

10.48308/piadm.2026.243252.1014

Abstract

This study investigates the chromium (Cr) coating deposited onto Zr cladding using the IR-MPF-100 plasma focus device. The primary objective was the quantitative assessment of phases and residual stresses at the nanoscale, linking them directly to strengthening mechanisms. X-ray diffraction (XRD) analysis confirmed the formation of Cr2O3and ZrO2 phases, with tetragonal and monoclinic ZrO2 coexisting within the oxide scale. Crucially, residual compressive stresses, determined from XRD peak shifts, revealed that the Cr2O3 phase exhibits the highest compressive stress and effective hardness. Conversely, monoclinic ZrO2 displayed the lowest values due to transformation-induced stress relaxation during cooling. Modeling demonstrated that the coating’s elevated Taylor and Hall–Petch stresses, resulting from high dislocation density and nanoscale grain size, manifest as these large compressive residual stresses. The Zr substrate played a minor role, acting primarily as a stress-accommodating medium. These findings provide a critical quantitative understanding of stress-strengthening interdependence in advanced Cr–Zr cladding coating systems.

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