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Your search keyword '"Nagasaka, Takuya"' showing total 5 results
Start Over Author "Nagasaka, Takuya" Publisher american nuclear society
5 results on '"Nagasaka, Takuya"'

1. Moderation of Negative Oxygen Effects by Small Yttrium Addition to Low Activation Vanadium Alloys

Author

MIYAZAWA, Takeshi, NAGASAKA, Takuya, HISHINUMA, Yoshimitsu, MUROGA, Takeo, LI, Yanfen, MIYAZAWA, Takeshi, NAGASAKA, Takuya, HISHINUMA, Yoshimitsu, MUROGA, Takeo, and LI, Yanfen

Abstract

In order to improve irradiation embrittlement of vanadium alloys for fusion reactors, yttrium (Y) has been added reducing the interstitial oxygen impurity. However Y addition can also degrade high-temperature strength, because Y could scavenge oxygen in solid solution, which is a strong hardening agent in vanadium alloys. In this study, the effect of Y addition and oxygen level on the mechanical properties was investigated from the view points of both the high-temperature strength and low temperature ductility. Y addition was suggested to moderate the hardening and embrittlement induced by oxygen impurity sustaining the high-temperature strength within an acceptable level., source:To cite this article: Takeshi Miyazawa, Takuya Nagasaka, Yoshimitsu Hishinuma, Takeo Muroga & Yanfen Li (2011) Moderation of Negative Oxygen Effects by Small Yttrium Addition to Low Activation Vanadium Alloys, Fusion Science and Technology, 60:1, 407-411, DOI: 10.13182/ FST11-A12390, source:https://doi.org/10.13182/FST11-A12390, identifier:0000-0001-6564-8922

Published
2022

2. THE CORROSION INFLUENCE OF PB-LI ON MICROSTRUCTURE AND MECHANICAL PROPERTIES

Author

yanfen, Li, Kondo, Masatoshi, Nagasaka, Takuya, Muroga, Takeo, and Valentyn, Tsisar

Subjects
Corrosion, ODS, liquid metal, fusion blanket, Microstructure, Pb-Li
Abstract

In this work, corrosion experiments on 9Cr-ODS and CLAM steels were carried out in static Pb-Li at 873 K for 250 h. Both steels showed weight loss and softening near the surface after the exposure. Tensile properties did not change and creep properties degraded slightly for 9Cr-ODS steel. In contrast, CLAM steel showed hardening by increase in tensile strength and creep rupture time, and decrease in minimum creep rate and reduction of area. The metallurgical analyses showed that the both steels were non-uniformly corroded by preferential corrosion at grain and sub-grain boundaries. Near the surface, carbides were lost and Cr was depleted to several tens of Pm depth. The depletion was heavier for 9Cr-ODS than for CLAM. The corrosion mechanism was proposed to be a loss of protective oxide layer followed by dissolution of Cr in matrix into liquid Pb-Li. The more pronounced corrosion effect on 9Cr-ODS than on CLAM may be due to finer grain and sub-grain size enhancing preferential attack by Pb-Li at the boundaries, or lack of Mn in 9Cr-ODS, which can form protective layers for CLAM.

Published
2011

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