| Abstract |
| The effect of high temperature oxidation on the mechanical properties of Zr-1Nb-1Sn-0.1Fe alloy cladding tubes were studied. The oxidation rate was far greater at 700℃than at600℃, reflecting the increasing volume fraction of porous monoclinic ZrO2. The ductility increased and strength decreased after oxidation at 600℃, suggesting softening due to recovery, and recrystallization was predominant over the ductility loss caused by oxidation. In the temperature range between 200℃and 450℃, the flow stress is greater in the oxidized Zr alloy than that annealed at 600℃in a vacuum, suggesting the increased contribution of dynamic strain aging associated with the diffusion of oxygen atoms into a Zr matrix. At 700℃, the ductility decreased significantly after oxidation due to crack propagation into the Zr alloy matrix from the brittle oxide. A stress plateau and a decrease in ductility were observed even in Zr-1Nb-1Sn-0.1Fe with thick brittle oxide after oxidation at 700℃ for 24 hrs in air, suggesting the deformation mechanism was not greatly affected by oxidation. |
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| Key Words |
| alloys, annealing, oxidation, tensile test, fuel cladding |
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