Effect of self-ion with high-energy irradiation on the surface morphology, microstructure and mechanical properties of nanocrystalline TiAlN coating

TiAlN coating are used as nuclear reactor cladding protective materials due to their good corrosion resistance. However, long-term exposure to an extremely harsh nuclear environment will cause degradation, and the threshold irradiation fluence is not clear. In this work, a nanocrystalline TiAlN coating was successfully deposited on 304 L stainless steel and silicon wafers by filtered cathodic vacuum arc (FCVA) technology. The effects of different fluences of Al³⁺ irradiation performed by the GIC4117 tandem accelerator on the structure and mechanical properties of TiAlN coatings were studied. After irradiation with a fluence of 4.0 × 10¹⁴ ions/cm², the refinement of grain size and columnar structure of nanocrystalline TiAlN coatings was confirmed, which improved the hardness. The irradiation fluence of 4.0 × 10¹⁶ ions/cm² reduces all mechanical properties and can be taken as the threshold for the degradation of the TiAlN coating. These nanocrystalline TiAlN coatings have high surface integrity with no destruction, such as flacking, exfoliation and blistering, and good mechanical properties after irradiation.