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The influence of microtexture on the formation mechanism of nodules in Zircaloy-4 alloy tube.
- Source :
- Journal of Materials Science & Technology; Jun2020, Vol. 47, p68-75, 8p
- Publication Year :
- 2020
-
Abstract
- Corrosion resistance of Zircaloy-4 alloy tube in superheated steam at 673 K/10.3 MPa is anisotropic. A part of the surface undergoes uniform corrosion while the other suffers nodular corrosion. Narrow and wide nodules are observed after an exposure period of 3 and 30 days, respectively. A new matrix transformation method is established in order to study the formation mechanism of nodules in the cross-section (CS) of Zircaloy-4 alloy tube using the EBSD technique, while the CS perpendicular to axial direction (AD). The results reveal that the microtexture is a key factor behind the two types of corrosion. Furthermore, the oxide layers grow anisotropically over the corroded surface. A thick oxide layer forms over the nodular corrosion region on the grains with c-axis oriented in the range of 40° around tangential direction (TD), whereas a thin oxide layer over the uniform corrosion region is detected on the grains with c-axis oriented in the range of 68° around TD. In short, the anisotropic growth of oxide layer was caused by the change of microtexture of the Zr-4 alloy tube, and this anisotropic growth of oxide layer contributed to the nodules formation. [ABSTRACT FROM AUTHOR]
- Subjects :
- T-matrix
SUPERHEATED steam
ALLOYS
TUBES
SUPERHEATERS
CORROSION resistance
Subjects
Details
- Language :
- English
- ISSN :
- 10050302
- Volume :
- 47
- Database :
- Supplemental Index
- Journal :
- Journal of Materials Science & Technology
- Publication Type :
- Periodical
- Accession number :
- 142765743
- Full Text :
- https://doi.org/10.1016/j.jmst.2020.02.010