The static creep and cyclic creep behaviors of annealed pure zirconium and Zircaloy-4 have been investigated at 673K and 773K in Hydrogen and Argon atmosphere. Also the transient tensile tests of the same materials were supported at 673K. The cyclic retardation of Zircaloy-4 and cyclic acceleration of pure Zr were observed. The cyclic retardation of Zircaloy-4 is due to the interaction of solute atom and mobile dislocation by which the increase in flow stress during the transient tensile test.
The stress dependency of creep rate in Zircaloy-4 was found to satisfy the exponential law rather than power law. In stress change during creep tests, the stress constants were not changed. It seems that there were a little or no dislocation cell structures.
At Hydrogen atmosphere, the Zirconium hydride precipitation and increase of primary creep strain was observed. The ratio of primary creep strain at Hydrogen atmosphere and Argon atmosphere was increased by increasing stress. The Hydrogen diffusion mechanism in Zircaloy-4 in this experimental conditions was stress induced diffusion.
The results of this study may be useful to study the cyclic creep properties of solid solution alloys.