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Vol.44, No.1, 44 ~ 55, 2006
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| Title |
| Prediction of Solidification Grain Structure in the Ni-Base Superalloy CM247LC |
| 서성문 Seong Moon Seo , 김인수 In Soo Kim , 이재현 Je Hyun Lee , 조창용 Chang Yong Jo , Keisaku Ogi |
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| Abstract |
| The solidification grain structure is one of the important features that have to be controlled in many casting processes. In order to predict the solidification grain structure in the Ni-base superalloy CM247LC, a three-dimensional cellular automaton (CA) model has been coupled with finite element (FE) heat flow calculations. In the CA-FE model, Gaussian distribution of nucleation sites was assumed to account for the heterogeneous nucleation in the bulk liquid and at the mold wall. The Kurz-Giovanola-Trivedi (KGT) model was extended to multi-component Ni-base superalloy to take account of the growth kinetics of the dendrite tip. For describing Gaussian distribution of nucleation sites at the mold wall, an empirical relationship between the surface grain density and the initial cooling time of the melt was proposed and applied to the input parameters in the present CA-FE model. The simulated grain structures were validated at various casting conditions by comparison with the corresponding experimental micrographs. The CA-FE predictions of grain structure are in good agreement with the experimental results. |
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| Key Words |
| Superalloy, CA-FE model, Grain structure prediction, Surface grain size |
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