DC Field | Value | Language |
---|---|---|
dc.contributor.advisor | Kim, In-Sup | - |
dc.contributor.advisor | 김인섭 | - |
dc.contributor.author | Yoo, Jong-Sung | - |
dc.contributor.author | 유종성 | - |
dc.date.accessioned | 2011-12-14T08:02:49Z | - |
dc.date.available | 2011-12-14T08:02:49Z | - |
dc.date.issued | 1991 | - |
dc.identifier.uri | http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=61599&flag=dissertation | - |
dc.identifier.uri | http://hdl.handle.net/10203/48797 | - |
dc.description | 학위논문(박사) - 한국과학기술원 : 핵공학과, 1991.8, [ x, 94 p. ] | - |
dc.description.abstract | The mechanical properties of Zircaloy-4 were investigated after quenched from the ($\alpha+\beta$) phase temperature. The resulted microstructure consisted of a mixture of hard primary $\alpha$ and soft transformed $\beta$ phases. At 1163K treatment the transformed $\beta$ phase showed isolated lath morphology, and at 1223K the transformed $\beta$ showed parallel plate Widmanstatten $\alpha$. The $\alpha/\beta$ transformation kinetics was comparable to Johnson-Mehl-Avrahmi equation and the activation energy for $\alpha\,\rightarrow\,\beta$ transformation was found to be 33Kcal/mole. Microhardness of constituent phases revealed that the strength of transformed $\beta$ phase was almost constant, while that of primary a increased due to smaller grain size and oxygen enrichment with increasing amount of transformed $\beta\,(f_{\alpha``}$) The 0.2\% yield and tensile strengths increased after the ($\alpha+\beta$) heat treatment. the plot of the yield strength against $f_{\alpha``}$ by the modified rule of mixtures showed that the yield strength was dependent on the strength and amount of primary $\alpha$ phase and on the interactions between the phases. For $f_{\alpha``}<0.3$, the calculated yield strength agreed well with the measured, showing that the interaction term was very small. For $f_{\alpha``}>0.3$, the calculated yield strength was lower than the measured and the deviation increased with increasing $f_{\alpha``}$ exhibiting that the interaction term was positive and increased with $f_{\alpha``}$. Two different stages of work hardening existed. Up to 0.015 total strain, the work hardening exponent n increased when the matrix was the hard primary $\alpha$ at 1163K treatment, but at 1223K n decreased as the soft transformed $\beta$ became the matrix and more continuous. Above the 0.015 strain, the work hardening exponent was similar to that of $\alpha$-annealed Zircaloy-4. Uniform elongation decreased remarkabley for small amount of transformed $\beta$ phase... | eng |
dc.language | eng | - |
dc.publisher | 한국과학기술원 | - |
dc.title | Effect of (α+β) heat treatment on the mechanical properties of zircaloy-4 | - |
dc.title.alternative | (α+β) 열처리가 Zircaloy-4 의 기계적 성질에 미치는 영향 | - |
dc.type | Thesis(Ph.D) | - |
dc.identifier.CNRN | 61599/325007 | - |
dc.description.department | 한국과학기술원 : 핵공학과, | - |
dc.identifier.uid | 000855254 | - |
dc.contributor.localauthor | Yoo, Jong-Sung | - |
dc.contributor.localauthor | 유종성 | - |
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