1999 Fiscal Year Final Research Report Summary
Fatigue crack growth behavior of interface crack in thermal barrier coating
| Project/Area Number |
10650077
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Nagaoka University of Technology |
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Principal Investigator |
MUTOH Yoshiharu Nagaoka University of Technology, Professor, 工学部, 教授 (00107137)
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| Co-Investigator(Kenkyū-buntansha) |
MIYASHITA Yukio Nagaoka University of Technology, Research Associate, 工学部, 助手 (00303181)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Thermal barrier coating / Fatigue / Fatigue crack growth / Interface crack / 高温 |
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| Research Abstract |
(1) Thermal barrier coated samples with Co-base super alloy substrate, NiCoCrAlY bond coat and 8wt%Y2O3-ZrO2 top coat were prepared.
(2) In order to perform a test of fatigue crack growth along interface between metal bond coat layer and ceramic top coat layer, a special jigs and specimens with starter notch introduced by EDM were developed.
(3) An interface crack could be successfully introduced ahead of the notch and it propagated along interface region with coalescing to inherent pores.
(4) Based on the results of BEM analysis, A crack along the interface between top coat and bond coat layers propagates under mixed mode conditions of mode I and mode II and mix mode ratio varies with crack extension.
(5) The crack growth behavior along the interface of dissimilar materials is controlled by the parameter Ki, while it under mix mode in homogeneous materials is controlled by the parameter K θ max.
(6) With increasing porosity of the top coat, Young's modulus decreases and hence K-value also decreases. However, since crack growth resistance also decreases, there will be the optimum porosity.
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