일방향응고시킨 Pivalic Acid-Ethanol 계에서의 Dendrite의 성장

초록

Transparent organic materials have been frequently used as an analog of the solidifying metallic materials, because their transparency permits an in-situ observation of the microstructural development during solidification through optical microscopy. Pivalic acid (PVA)-ethanol system showing an anisotropic property in solid-liquid interfacial energy and interface kinetics was adopted in the present experiment, and the detailed experiments performed are as follows: ① variation of dendrite tip temperature with growth velocity, ② correlation between primary dendrite arm spacing (λ1) and the growth orientation away from the heat flow direction (tilt angle: θ), ③ variation of dendrite tip radius (R) with growth velocity (V), ④ dendrite tip stability parameter (σ*) and its dependence on the concentration. Concerning the correlation between the dendrite tip temperature and growth velocity the present result is well suited to Hunt-Lu equation. As the tilt angle increases, the average primary dendrite spacing tends to increase.

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