2006 Fiscal Year Final Research Report Summary
Development of Novel Aluminizing Process for Advanced High Temperature Structural Materials and Prediction of Their Microstructural Evolutions.
| Project/Area Number |
16360343
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | National Institute for Materials Science (2005-2006)
The University of Tokyo (2004) |
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Principal Investigator |
MURAKAMI Hideyuki National Institute for Materials Science, Composites and Coatings Center, Chief Researcher, コーティング・複合材料センター, 主席研究員 (30343867)
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| Co-Investigator(Kenkyū-buntansha) |
ODE Machiko National Institute for Materials Science, Computational Materials Science Center, Researcher, 計算科学センター, 研究員 (50370309)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Aluminizing treatment / Ni-base single crystal super alloy / Ir / Pt / High temperature oxidation / High temperature corrosion / Bond coat / orientation dependence |
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| Research Abstract |
The aluminizing process is one of the main techniques of enhancing oxidation and hot corrosion resistances of substrate Ni-base super alloys, which are used under very high temperatures such as blades and vanes of gas turbines or jet engines. This project dealt with Ni-base single crystal super alloys as substrate materials and Ir-base alloy modified aluminized coatings as oxidation resistant coatings, and focused on the following points. I. To systematically investigate the relationship between aluminizing conditions and resulting concentration profiles of Al and microstructural changes. II.To find out the best combination between oxidation and mechanical properties at high temperature. III. To develop a new model which can predict the microstructural changes by the aluminizing process. It is found that addition of 30 to 50 at % Ir to Pt-modified aluminized coatings followed by aluminizing at 1273 K for 5 h demonstrated enhanced oxidation and hot corrosion properties. The trace amount of Hf addition further enhanced the oxidation and hot corrosion properties. The additional new finding obtained in this project is that formation of secondary reaction zone (SRZ) is dependent on pre-surface treatment, and crystal orientation of single crystal substrates. Single crystal substrates whose surfaces were mechanically polished exhibited accelerated SRZ formation along <110>{001} while decelerated along <100>{001} direction. It should also be noted that Phase Field Simulation was applied to predict the microstructural changes caused by coatings, which confirmed that formation of additional phases differs between simply aluminized substrates and Ir coated and aluminized substrates.
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