Effect of hydrogen on the creep of the ultrafine-grained zirconium Zr-1Nb alloy at 673Â K

Comparative studies of the effect of hydrogenation to concentrations of 0.33 wt% on the behavior of the creep of Zr-1wt% Nb (hereinafter Zr-1Nb) alloy in fine-grained (dav = 4 μm) and ultrafine-grained (dav = 0.45 μm) states are performed for the creep rates in the interval 10−7-10−5 s−1 at a temperature of 673 K. Hydrogenation to concentration of 0.33 wt% is found to lead to a decrease in the steady creep rate and increase in the time to failure with simultaneous decrease in the value of deformation to failure. Possible mechanisms of deformation of the ultrafine-grained alloy under examined creep conditions are discussed.