Microstructural investigation of Alloy 617 corroded in high-temperature helium environment

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• 作者：Gyeong-Geun Lee ; ^{gglee@kaeri.re.kr" class="auth_mail} ; Sujin Jung ; Daejong Kim ; Yong-Whan Jeong ; Dong-Jin Kim
• 刊名：Nuclear Engineering and Design
• 出版年：May, 2014
• 年：2014
• 卷：271
• 期：Complete
• 页码：301-308
• 全文大小：2655 K

文摘

The high-temperature corrosion behavior of Alloy 617, which is a candidate material for the intermediate heat exchanger (IHX) in a very high-temperature gas-cooled reactor (VHTR), was investigated. The corrosion tests were carried out at 850-950 掳C in impure helium environments. All specimens showed a parabolic oxidation behavior at up to 250 h, and the activation energy for the rate constants of the mass change was similar to the activation energy for Cr/Cr₂O₃ oxidation in air. SEM micrographs revealed the evolution of the outer oxide layer, internal oxide, and depleted zone of the grain boundary carbides. Corrosion test in a pure helium environment showed that the minor impurity gases in helium environment affected the oxidation kinetics of Alloy 617. It is suggested that the control of minor impurities in a VHTR helium environment is necessary to apply Alloy 617 to an IHX material in a VHTR.