1988 Fiscal Year Final Research Report Summary
Microchemical Evolution in Alloys by Ion Irradiation and Fundamental Research for Creation of New Materials
| Project/Area Number |
60420053
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Nuclear engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
ISHINO Shiori Faculty of Engineering, University of Tokyo, Professor, 工学部, 教授 (70010733)
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| Co-Investigator(Kenkyū-buntansha) |
SEKIMURA Naoto Faculty of Engineering, University of Tokyo, Lecturer, 工学部, 講師 (10183055)
TAKAHASHI Naoaki Faculty of Engineering, University of Tokyo, Research Associate, 工学部, 助手 (80010966)
IWATA Shuichi Faculty of Engineering, University of Tokyo, Associate Professor, 工学部, 助教授 (50124665)
KAWANISHI Hiroshi Faculty of Engineering, University of Tokyo, Research Associate, 工学部, 助手 (40010970)
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| Project Period (FY) |
1985 – 1987
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| Keywords | Ion Irradiation / Creation of New Materials / Radiation-enhanced segregation / Radiation-modified Phase Transformation / Radiation-enhanced Precipitation / Voids / 時効効果 |
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| Research Abstract |
Microchemical evolution in ion-irradiated alloys is analyzed by energy dispersive X-ray spectroscopy (EDS). Non-equilibrium segregation or depletion of alloying elements is observed in austenitic steels irradiated with heavy ions at elevated temperatures. Ni and Si are enriched around cavities and grain boundaries, while Cr, Mn and Mo are depleted there. These are explained by size factors of these elements. Ni-rich phases which are not seen in thermally controled material affect microstructural evolution during irradiation. MC precipitates in austenitic steels have strong stability during irradiation, while segregation of Ni and Si to their surface can modify the precipitates.
Microstructural and microchemical evolution in ion-irradiated alloys strongly depends on both energy and species of injected ions. For example, 400 HeV P^+ ion irradiation to austenitic steels produces iron-phosphide around the depth of ion range, and these precipitates supress void formation under irradiation.
Ion irradiation to precipitation-hardened ferritic steel promotes transition of martensitic phase to austenitic phase, which is not observed by thermal aging.
Non-equiliburium segregation and precipitation are found in various kinds of alloys during ion irradiation. Enormous data to control the creation of new materials by irradiation with energetic ions have been extracted from the present study.
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