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Vol.43, No.3, 195 ~ 202, 2005
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| Title |
| Reorientation of Hydrides and Its Effect on the Mechanical Properties of Zircaloy-4 Cladding Tubes |
| 이강욱 Kang Wook Lee , 이상용 Sang Yong Lee , 최원욱 Won Wook Choi , 김필환 Phil Whan Kim , 최재하 Jae Ha Choi , 홍순익 Sun Ig Hong |
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| Abstract |
| The reorientation of hydrides and its effect on the fracture of Zircaloy-4 cladding tubes with the hydrogen content of 220 wt. ppm were investigated. The reorientation of hydrides along the radial directions was most pronounced if the tube was cooled from 300℃ to 200℃ under circumferential loading. Reorientation occurred much less frequently in either higher (cooled from 400℃ to 300℃) or lower (cooled from 200℃ to 100℃) temperature range. The reorientation of hydrides was found to increase with the increase of loading time, suggesting time dependent stress-aided dissolution of circumferential hydrides (hydride platelets in the circumferential-axial plane) and reprecipitation of radial hydrides (hydride platelets lying in to radial-axial plane). The strength and ductility decreased with the reorientation of hydrides. The strength decreased to ~380 MPa and the ductility decreased to zero in the tube which was reorientation-treated from 300℃ to 200℃ (R43AC). Fracture surface of R32AC sample exhibited flat cleavage fracture along the radial hydride platelet. (Received October 29, 2004) |
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| Key Words |
| Hydrides, Zircaloy-4, Reorientation, Ductility, Strength |
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