Elucidation of intergranular stress corrosion cracking crack growth mechanism of the Ni-base high-Cr alloy and creation of their maintainability

2015 Fiscal Year Final Research Report

• Project/Area Number: 25289348
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Nuclear engineering
• Research Institution: Tohoku University
• Principal Investigator: Yonezawa Toshio 東北大学, 未来科学技術共同研究センター, 産学官連携研究員 (10422081)
• Co-Investigator(Kenkyū-buntansha): WATANABE MASASHI 東北大学, 未来科学技術共同研究センター, 准教授 (60312659) ; TAKEDA YOICHI 東北大学, 工学研究科, 准教授 (40374970)
• Co-Investigator(Renkei-kenkyūsha): SHOBU TAKAHISA 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 量子ビーム応用研究センター, 主任研究員 (90425562)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 応力腐食割れ / 結晶粒界 / 粒界炭化物 / 冷間加工 / Ni基高Cr合金 / き裂進展速度 / 方射光 / 透過電子顕微鏡観察

Outline of Final Research Achievements

In order to clarify the intergranular stress corrosion crack growth mechanism of the Ni-base high-Cr alloys, the measurement of stacking fault energy value by high-resolution transmission electron microscopy, observation of grain boundary carbides with high performance ion polishing process, measurement of local stress-strain near the grain boundaries and near exposed surface generated by the surface oxides of the material by In-situ Synchrotron X-ray technique were achieved from the viewpoint of material, stress and environmental aspects, such as the oxidation of the residual eutectic carbides at the time of melting process for the Ni-base high-Cr alloy, reducing of the local stacking fault energy value near grain boundaries, increasing of the tensile local residual stress and strain near the exposed surface of the material due to the surface oxide film formation, and near the grain boundaries, and elucidation of the oxidation behavior in situ under corrosive environment.

Free Research Field

原子力材料、腐食、金属