| Project/Area Number |
25282106
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Partial Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Social systems engineering/Safety system
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| Research Institution | Shonan Institute of Technology |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
TABUCHI Masaaki 国立研究開発法人物質・材料開発機構, 高温材料グループ, グループリーダー (60354239)
HIRAO Masahiko 大阪大学, 基礎工学研究科, 教授 (80112027)
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| Project Period (FY) |
2013-04-01 – 2016-03-31
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| Project Status |
Completed (Fiscal Year 2015)
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| Budget Amount *help |
¥15,730,000 (Direct Cost: ¥12,100,000、Indirect Cost: ¥3,630,000)
Fiscal Year 2015: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2014: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2013: ¥10,660,000 (Direct Cost: ¥8,200,000、Indirect Cost: ¥2,460,000)
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| Keywords | クリープ / 非線形超音波 / タイプ4損傷 / 非接触計測 / 損傷評価 / クリープ損傷 / タイプ４損傷 |
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| Outline of Final Research Achievements |
We investigated the relationship between microstructural changes and the evolutions of two nonlinear acoustic characterizations: resonant frequency shift and three-wave mixing, with electromagnetic acoustic resonance throughout the creep life in the welded joints of ASME Gr.91 (9Cr-1Mo-VNb) and Gr.122 (11Cr-0.4Mo-2W-CuVNb) heat resistant steels and the correlation between two nonlinear acoustic characterizations. Creep tests with thick-welded joint specimens were carried out at 873 K, and 90 MPa in Gr.91 and 100 MPa in Gr.122 and interrupted at several time steps. Two nonlinear acoustic parameters and ultrasonic attenuation decreased from the start to 20% in Gr.91 and 50% in Gr.122 of creep lives. After slightly increased, they rapidly increased from 30% in Gr.91 and 80% in Gr.122 of creep lives to rupture. We interpreted these phenomena in terms of dislocation recovery, recrystallization, and restructuring related to the initiation and growth of creep void.
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