Effect of Flow on Dimensions of Dendrite in Undercooled Melt

流动对过冷熔体中枝晶尺寸的影响

• 批准号: 08650867
• 负责人: MIYATA Yasunori
• 金额: $ 1.34万
• 依托单位: Nagaoka University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650867/
• 关键词: undercooled solidification; loop cell; interfacial stability; alloy; dendrite; convection; 凝固; 局所平衡; 成長速度; 温度勾配; 対流; 界面形態; 融液; 流動

Melt flow affects dimensions of dendrite in the solidiflcation in undercooled melt. It is important to study the effect of melt flow on the dimensions, because the dimensions are very much corelated to the microsegregation of solute. The effect of melt flow on the domensions is studied in this work.Dimensions of dendrite are, in general, determined through the transport of heat and solute. The solidification in undercooled melt is controled by the heat transport alone. The effect of melt flow on the dimensions of dendrite is studied in the solidification for pure material, experimentally and theoretically. Then the effect of melt flow on the dimensions of dendrite is studied for alloy in this work.In order to introduce the flow in the melt, a loop cell with circular cross section is designed and manufectured. The melt flow was drived by the buoyancy force by heating a part of the cell. The velocity of the stream was controled by the electric power applied to the heater.Melt flow makes the growth rate of dendrite increase for the solidification in a given undercooling. The effect of melt flow on the dimensions is significant for the solidification in low undercooling. These are observed in the solidification for the pure material and also for the alloy.It was explained theoretically that the cooler melt coming to the tip of dendrite makes the temperature gradient at the tip, and the growth rate has to increase to maintain the heat/solute conservation. The longer interaction time between the melt flow and dendritic body makes the effect of melt flow significant for the solidification in undercooled melt.

熔体流动会影响底层熔化熔体中固体叶片的尺寸。重要的是研究熔体流对尺寸的影响，因为尺寸非常与溶质的微层次进行融合。在这项工作中研究了熔体流对圆顶的影响。通常，树突的维度是通过热和溶质的运输来确定的。单独的热运输能够控制过冷熔体中的凝固。在实验和理论上，研究了熔体流对树突尺寸的影响。然后在这项工作中研究了合金的熔体流动对树突尺寸的影响。为了在熔体中引入流量，设计和制定了带有圆形横截面的环电池。通过加热细胞的一部分，浮力通过浮力驱动熔体。流的速度是通过施加到加热器的电力控制的。融化流量使给定冷却液中固化的树突增长速度增加。熔体流对尺寸的影响对于低底冷的固化很重要。这些在纯材料的固化中也可以观察到，从理论上讲，它的冷却器熔体呈降落液的尖端使温度梯度在尖端处，并且必须增加生长速度以维持热/溶质保护。熔体流量和树突体之间的较长相互作用时间使熔体流动的效果显着，对于底层熔化熔体中的凝固。