서지주요정보
알루미늄 합금의 응고조직과 열전달현상에 대한 GPa 가압력의 영향 = Effect of GPa pressure on microstructures and heat transfer phenomena of aluminum alloys during solidification
서명 / 저자 알루미늄 합금의 응고조직과 열전달현상에 대한 GPa 가압력의 영향 = Effect of GPa pressure on microstructures and heat transfer phenomena of aluminum alloys during solidification / 한요섭.
저자명 한요섭 ; Han, Yo-Sub
발행사항 [대전 : 한국과학기술원, 1994].
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소장정보

등록번호

8005064

소장위치/청구기호

학술문화관(문화관) 보존서고

DMS 94017

휴대폰 전송

도서상태

이용가능

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초록정보

The effect of applied pressure from gravity up to 1.7 GPa during solidification of Al-5.4wt%, 35wt%Cu and 5wt% Fe alloy on the microstructure and heat transfer phenomena have been investigated. The cooling rate of Al-Cu alloy increased with increasing the pressure up to GPa level, but it was not linearly increased. The dendrite arm spacing of Al and eutectic spacing of $Al-CuAl_2$ refined with the increase of pressure up to 1.7 GPa during solidification, and also it's microstructures were more refined than thoses of gravity cast under the condition of the same cooling rate. From the results of experimental work, applied pressure during solidification enhanced both cooling rate and undercooling. The thermodynamic undercooling by Clausius-Claypeyron equation was dominant factor of microstructural refinement under GPa pressure. In Al-5.4wt%Cu alloy solidified under GPa pressure, volume fration of interdendritic eutectics were decreased and large of metastable $\theta'$ at interdendritic Al boundary was formed. It can be thought by increasing of solid solubility by high pressure phase equilibria. The primary $CuAl_2$ in hypereutectic Al-35wt%Cu and $Al_{13}Fe_4$ in Al-5wt%Fe alloy were transition to regular eutectic under the pressure of GPa, and it was due to the enhanced thermodynamic undercooling by changing of the growth mechanism to coupled zone of eutectic. The eutectics of $Al-CuAl_2$ were grown near by the condition of maximum stability and the irregularity of eutectic growth, $\psi(\overline{\lambda}/lambda_m$, was 3.2. The growth of primary $CuAl_2$ was controlled by facets at the tip and dendritic growth of $CuAl_2$ under GPa pressure was promoted. A theoretical model was developed and analysed to predict the interfacial heat transfer coefficient during solidification as function of interface contact ratio, contact gap thickness, thermal properties and interfacial conditions. The changes of heat transfer coefficient according to applied pressures were approximated by the cooling rates measured, comparing with the theoretical cooling curves calculated by 2-dimensional solidification analysis. The heat transfer coefficient of Al-Si alloys was about $10^3W/m^2K$ in gravity and increased to $10^4W/m^2K$ under the pressure of 110 MPa, to $10^5W/m$^2K$ under the GPa.

서지기타정보

서지기타정보
청구기호 {DMS 94017
형태사항 iv, 116 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Yo-Sub Han
지도교수의 한글표기 : 이호인
공동교수의 한글표기 : 김영길
지도교수의 영문표기 : Ho-In Lee
공동교수의 영문표기 : Young-Gil Kim
학위논문 학위논문(박사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 113-116
주제 Heat --Transmission.
Solidification.
Pressure.
알루미늄 합금. --과학기술용어시소러스
응고 조직. --과학기술용어시소러스
가압. --과학기술용어시소러스
열 전달. --과학기술용어시소러스
Alumium-copper alloys.
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