| Title |
Reorientation of Hydrides and Its Effect on the Mechanical Properties of Zircaloy-4 Cladding Tubes |
| Authors |
이강욱(Kang Wook Lee); 이상용(Sang Yong Lee); 최원욱(Won Wook Choi); 김필환(Phil Whan Kim); 최재하(Jae Ha Choi); 홍순익(Sun Ig Hong) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Hydrides; Zircaloy-4; Reorientation; Ductility; Strength |
| 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) |