Modeling dendrite growth in undercooled concentrated multi-component alloys

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• 作者：Kang Wang ; Haifeng Wang ; Feng Liu ; ^{liufeng@nwpu.edu.cn} ; Haimin Zhai
• 关键词：Multi-component ; Concentrated ; Dendrite growth ; Rapid solidification
• 刊名：Acta Materialia
• 出版年：2013
• 出版时间：June, 2013
• 年：2013
• 卷：61
• 期：11
• 页码：4254-4265
• 全文大小：1805 K

文摘

Most theoretical work on dendrite growth has focused on dilute binary alloys, while most industrial alloys are concentrated multi-component systems. By incorporating the local non-equilibrium effects both at the interface and in the bulk liquid, the thermodynamic database and diffusional interaction, a model was developed for dendrite growth in undercooled concentrated multi-component alloys. An experimental study of dendrite growth in undercooled Ni-18 at. % Cu-18 at. % Co melts was carried out and the measured interface velocities (V) were well predicted by the present model over the whole undercooling range (¦¤T = 30-313 K). During dendrite growth the partition coefficients change non-monotonically due to interaction between the species and changes in the dendrite tip radius. Interaction between the species also leads to a lower interface velocity and larger ¦¤T and V as the ¦¤T-V relation plateaus. The previous definition of constitutional undercooling, i.e. the sum of the contributions of each solute, is not applicable to concentrated multi-component alloys. The controlling mechanisms during dendrite growth are discussed with respect to the results of the calculations.