Atomic scale observation of grain boundary segregation in nuclear materials by atom probe tomography and study on mechanism of grain boundary degradation

2014 Fiscal Year Final Research Report

• Project/Area Number: 24246155
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Nuclear engineering
• Research Institution: Tohoku University
• Principal Investigator: NAGAI Yasuyoshi 東北大学, 金属材料研究所, 教授 (10302209)
• Co-Investigator(Kenkyū-buntansha): INOUE Koji 東北大学, 金属材料研究所, 准教授 (50344718) ; TOYAMA Takeshi 東北大学, 金属材料研究所, 講師 (50510129) ; SHIMIZU Yasuo 東北大学, 金属材料研究所, 助教 (40581963) ; NAGUMO Kazuaki 東北大学, 金属材料研究所, 助教 (40719259)
• Co-Investigator(Renkei-kenkyūsha): NISHIYAMA Yuataka 独立行政法人日本原子力研究開発機構, 安全研究センター, グループリーダー (60414596) ; KATSUYAMA Jinya 独立行政法人日本原子力研究開発機構, 安全研究センター, 研究副主幹 (00403155)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 粒界偏析 / 粒界脆化 / 3次元アトムプローブ / 原子炉高経年化

Outline of Final Research Achievements

We have studied the microstructural changes of the structural materials of the nuclear reactors, which are very important for the integrity of the reactors, exposed by long-term neutron irradiation followed by the unexpected temperature rise above 450oC by using state-of-the-art nanoscale techniques, and have revealed the effects on the mechanical properties. The obtained results showed the different behavior in the irradiated materials from that in un-irradiated materials after the high temperature exposure. For example, the coarsening of irradiation induced Cu-rich precipitates in surveillance specimens of a rector pressure vessel are observed. The complementary theoretical calculation revealed the relationship between the microstructural changes and mechanical property changes.

Free Research Field

工学