The effect of temperature modulation on morphological instability of a binary alloy
碩士 === 國立中央大學 === 機械工程研究所 === 92 === The main goal of this thesis is to investigate into the influence of temperature modulation on the morphological stability of directional solidification. We study the morphological instability of the melt-solid interface of a dilute binary alloy. The alloy is ass...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2004
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| Online Access: | http://ndltd.ncl.edu.tw/handle/06792624088913839094 |
| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 92 === The main goal of this thesis is to investigate into the influence of temperature modulation on the morphological stability of directional solidification. We study the morphological instability of the melt-solid interface of a dilute binary alloy. The alloy is assumed to undergo directional solidification into a modulated temperature field. Under such a circumstance, the molten zone is oscillated back and forth in a periodic way. The basic state is solved analytically assuming the melt-solid interface is flat and the bulk melt is quiescent by expanding the governing equation in terms of the assumed infinitesimal modulation amplitude. By further neglecting the flow field, we investigate the interfacial stability of the base state by considering two specific instability modes: the synchronous and sub-harmonic modes. The synchronous modes vary with time having the same frequency as that of the oscillatory molten zone, while the sub-harmonic modes are of the half frequency.
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