1994 Fiscal Year Final Research Report Summary
Development and Application of the simultanious electron, X-ray and gamma-ray Mossbauer Detector
| Project/Area Number |
05555184
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Structural/Functional materials
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| Research Institution | Osaka University |
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Principal Investigator |
NASU Saburo Osaka University, Faculty of Eng.Science, Associate prof., 基礎工学部, 助教授 (00030057)
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| Co-Investigator(Kenkyū-buntansha) |
MORIMOTO Kazuo Mitsubishi Heavy Industries, Co.Ltd.Chief Researcher, 技術本部高砂研究所, 主任(研究者)
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| Project Period (FY) |
1993 – 1994
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| Keywords | non-destructive testing / ^<57>Fe Mossbauer spectroscopy / large scale components / duplex-stainless steel / thermally induced brittleness / hyperfine magnetic field / ferrite / austenite |
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| Research Abstract |
Backscattering Fe Mossbauer detector has been developed for the use in in-situ non-destructive testing of the large scale component like steel building wall, ships and so on. This detector can make possible to count the internal conversion electrons, backscattered X-ray and gamma-ray, simultaniously and measure the so called backscattering Mossbauer spectrum which can indicate the change in microscopic structure of steels and materials containing iron. Using this detector, the microstructural change in duplex-stainless-steel has been investigated by the bacscattering Mssbauer spectra obtained by the conversion electron, X-ray and gamma-ray. Commercial duplex-stainless-steel has usually been manufactured by a continuous casting technique and consists of a paramagnetic austenite and a ferromagnetic ferrite phase. ^<57>Fe Mossbauer spectra obtained from the duplex-stainless-steel consist of two components. One is a predominant component of the single resonance line rising from a paramagnetic austenite and the other is a minor component of a magnetically split sextet rising from ferromagnetic ferrite. Paramgentic austenite has a face-centered cubic (fcc) structure and a quite stable for heat treatments by annealing at elevated temperatures, but ferromagnetic ferrite has a body-centered cubic (bcc) structure and shows a phase decomposition by annealing at appropriate temperatures. Present Mossbauer study shows clearly that a phase decomposition occurred in ferrite of duplex-stainless steel by annealing at rather low temperature like 723 K.^<57>Fe Mossbauer spectra from ferrite show a change in magnitude of the averaged hyperfine magnetic fields suggesting a change in Cr concentration in ferrite by annealing.
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Research Products
(4 results)
