| Abstract |
| Nb solubility and phase boundary in Zr-rich region of Zr-Nb binary alloy system were investigated using sponge Zr containing 700 ppm Fe and 700 ppm O. Characteristics of microstructures of the isothermally annealed specimens was analyzed by hardness measurement, OM, SEM and TEM. The transformation temperature from alpha to beta in the pure Zr and the monotectoid temperature were 930±3℃ and 585±3℃, respectively. It was not consistent with the previous result by Cox where transformation temperature and the monotectoid temperature are 863℃ and 610℃, respectively. The Nb solubility measured using TEM in this study was 0.2 wt.%, which was lower than 0.6 wt.%, measured using OM by Cox. It can be concluded that the oxygen contained in sponge Zr played a role to increase the transformation temperature of alpha to beta and to decrease the monotectoid transformation temperature. |
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| Key Words |
| Zr , Zr-Nb , Fuel cladding , Phase diagram , Phase transformation |
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