| タイトル | A New Analytical Approach to Predict Spacing Selection in Lamellar and Rod Eutectic Systems |
| 著者（英） | Catalina, Adrian V.; Sen, Subhayu; Whitaker, Ann F. |
| 著者所属（英） | Universities Space Research Association |
| 発行日 | 2001-01-01 |
| 言語 | eng |
| 内容記述 | In this paper, we reexamine the Jackson and Hunt (JH) theory and relax the assumption of isothermal solid/liquid interface(SLI) used in their treatment. A modification of the term B. in the expression of the solute concentration profile is also proposed. Based on the predictions of this modified theory the traditional definitions of regular and irregular eutectics are discussed. For regular eutectics the new model identifies a range of spacing within the limits defined by the minimum undercooling of the alpha and beta phase. For the irregular Al-Si eutectic system in particular we identified two different spacing selection mechanisnis: a) for a particular growth rate, a nearly isothermal interface can be achieved at a unique minimum spacing lambda(sub I); b) the average spacing in the microstructure (lambda(sub av) > lambda(sub I)) is essentially dictated by the undercooling of the faceted phase. Based on the modified theoretical model a semi-empirical expression has been developed to account for the influence of the temperature gradient. The theoretical calculations have been found to be in good agreement with the published experimental measurements. |
| NASA分類 | Metals and Metallic Materials |
| 権利 | No Copyright |
