Microstructural and Mechanical Response of CuCrZr Irradiated with High-Energy Neutrons

CuCrZr alloys, known for high thermal conductivity and mechanical integrity, are widely used in nuclear reactor components. In this work, CuCrZr samples were subjected to high-energy neutron irradiation at low fluence and analyzed using scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS), X-ray diffraction (XRD) with Williamson–Hall (W–H), nanoindentation, and neutron activation studies. ACTYS predictions, validated through gamma spectroscopy, confirmed 64 Cu as the major activity isotope, with short-lived isotopes driving rapid decay, along with > 1 MeV prompt gamma photon emission. SEM–EDS revealed Cr-rich precipitates and possible F-centers, while XRD indicated Cr precipitation, full width at half-maximum (FWHM) reduction with a measurable lattice parameter shift, higher mass absorption coefficient, and compressive stress. Williamson–Hall analysis showed grain growth, increase in dislocation density, and uniform deformation energy density model (UDEDM) analysis confirmed a nearly order-of-magnitude rise in overall defect density. Nanoindentation showed both hardness and modulus increment after the irradiation. These results demonstrate that low-fluence neutron irradiation induces activation, defect formation, and precipitation in CuCrZr, leading to an increase in hardness and elastic modulus.