| Project/Area Number |
10305052
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
NARITA Toshio Hokkaido Univ. Grad. School of Eng., Professor, 大学院・工学研究科, 教授 (60001252)
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| Co-Investigator(Kenkyū-buntansha) |
KUROKAWA Kazuya Hokkaido Univ., Grad. School of Eng., Assoc. Professor, 大学院・工学研究科, 助教授 (00161779)
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| Project Period (FY) |
1998 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥32,170,000 (Direct Cost: ¥31,300,000、Indirect Cost: ¥870,000)
Fiscal Year 2001: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2000: ¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1999: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1998: ¥20,700,000 (Direct Cost: ¥20,700,000)
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| Keywords | Fe-25Cr alloy / Cr_2O_3 / Crack / Creep / Secondary creep rate / Ar atmosphere / 973K / 加速腐食 / 粒界腐食 / スケールの破壊 / 強度強化 / 亜硫酸ガス / 応力・歪み極性 / スケールの密着性 / 酸化 / 硫化 / スケール破壊 / ステンレス鋼 / クロム酸化物 / 粒界すへり / 耐熱材料 / 結晶粒界 / 硫化腐食 / タービン / ボイラー / サーボパルサー |
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| Research Abstract |
A 0.1 μm thick Cr_2O_3 scale formed on an Fe-25Cr alloy in Ar at 973K for 7.2 ks, and then constant loads of 30-40 MPa were applied at 973K in Ar to the specimen. During creep deformation of the specimen the scale cracked at the end of the third creep stage at the grain boundaries, and then propagated into inner grains in the third creep stage. Cracks arrayed perpendicular to the stress loading direction and inter-crack spacings in the grain boundaries on the specimen are shorter than that of in the inner grains. Strain rate in each area is estimated. Inter-crack spacings (L) have power law relations with the creep rate of specimens (ε') as a form of L ∝ (ε')^n. Strain rate exponentη is estimated as -0.44 for the alloy grain boundaries and -0.22 for the alloy grains in this study.
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