Rapid solidification of highly undercooled Si and Si–Co melts
Rapid solidification of highly undercooled Si and Si–Co melts
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高度过冷的硅和硅钴熔体的快速凝固
DOI：
10.1063/1.2200467
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发表时间：
2006
影响因子：
4
通讯作者：
D. Herlach
中科院分区：
文献类型：
--
作者：
C. Panofen;D. Herlach
我们提出了直接的实验观察纯Si和稀Si 100 −xCox合金（x=0.1，0.5和2.5at.%）的过冷熔体中的生长速度和形态。发现了Si-Co合金生长速度-过冷度关系的反常行为，即在临界过冷度ΔT* 处出现突变，该突变取决于Co的浓度。与纯Si相比，即使考虑界面处的非平衡效应如溶质捕获，Si-Co合金中的反常生长行为也不能用现有的枝晶生长理论来描述。生长形貌随过冷度和Co浓度的增加而发生本质变化。
We present direct experimental observations of growth velocity and morphology in undercooled melts of pure Si and dilute Si100−xCox alloys (x=0.1, 0.5, and 2.5at.%). An anomalous behavior in the growth velocity-undercooling relation of the Si–Co alloys is found, exhibiting an abrupt break at a critical undercooling ΔT* which depends on Co concentration. In contrast to pure Si, the anomalous growth behavior in Si–Co alloys cannot be described by current dendrite growth theory even if nonequilibrium effects at the interface as solute trapping are taken into account. The growth morphology changes essentially with increasing undercooling and Co concentration.