2015 Fiscal Year Final Research Report
Synergistic creep strengthening mechanism by dislocations and precipitates in ferritic heat-resistant steels
| Project/Area Number |
26820317
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Structural/Functional materials
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| Research Institution | Kyushu University |
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Principal Investigator |
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| Project Period (FY) |
2014-04-01 – 2016-03-31
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| Keywords | フェライト系耐熱鋼 / クリープ / 強化機構 / 炭化物 / SEM / 結晶方位分布 / 粒界性格 |
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| Outline of Final Research Achievements |
In conventional ferritic heat-resistant steels with 9% Cr, the creep strength at an elevated temperature is improved by a combination of dislocation strengthening and M23C6 carbide strengthening. The M23C6 carbides are almost located on the grain boundaries in the lath martensite. In this study, we quantified some carbide parameters on each boundary using SEM techniques and discussed the effect of boundary character on the M23C6 carbides distribution. The M23C6 carbides size and coverage as function of creep time on each boundary in crept Gr. 91 steels were estimated using SEM-BSE images and SEM-EBSD analyses. Those parameters obviously had a dependency on the boundary character. On the prior γ grain boundary, the coverage was the highest before creep but it was drastically decreases with increasing creep time because the carbides were quickly coarsened.
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| Free Research Field |
金属物性
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