Hydrogen Kinetics and Hydride Formation Effect on Zr-1Nb and Zr-1Nb-1Sn-0.1Fe Alloys for Nuclear Application

The purpose of this study was to investigate the kinetics of hydrogen absorption and hydride formation and their effect on the mechanical properties in Zr-1Nb and Zr-1Nb-1Sn-0.1Fe alloys, which were thermomechanically processed and gaseously hydrided at 320ºC under 10 bar hydrogen pressure. X-ray diffraction (XRD) confirmed the formation of α-Zr matrix after final heat treatment. The alloys absorbed almost the same amount of hydrogen, although with different kinetics. Absorption began almost immediately in Zr-1Nb alloy whilst in Zr-1Nb-1Sn-0.1Fe hydrogen absorption started after 11 h besides a faster hydrogen kinetics. Results showed that tensile strengths for both alloys were nearly independent of absorbed hydrogen. Fractographic examinations indicated ductile fractures for unhydrided condition whereas quasi-cleavage features were observed for all hydrided specimens.