Microstructural investigation of irradiation damage behavior of proton irradiated Zr-1 wt.% Nb fuel cladding alloy

In the present study the irradiation damage behavior of Zr-1 wt.% Nb fuel cladding alloy was investigated using X-ray diffraction (XRD), positron annihilation lifetime spectroscopy (PALS), transmission electron microscopy (TEM) and nano-indentation. The samples were irradiated at two different fluences of 5 × 1016 p/cm2 and 1 × 1018 p/cm2 using proton beam of 3.5 MeV energy at room temperature. SRIM calculation showed an inhomogeneous damage distribution as a function of proton penetration depth with maximum damage at a depth of 68 μm. XRD analysis revealed variation in the microstructural parameters of irradiated samples after proton irradiation. PALS showed formation of open volume defects in the irradiated samples and a clustering tendency of the same with irradiation. The formation of − and − type dislocation loops and needle-shaped precipitates upon irradiation was demonstrated by TEM. The depth dependent hardness of the irradiated samples evaluated from nano-indentation technique was found to follow the damage distribution predicted by SRIM simulation.