서지주요정보
상온에서 순수 Al 의 static creep 과 cyclic creep 변형시 형성된 전위 구조의 비교 = Comparision of the dislocation structures in cyclically and statically crept pure aluminum at 0.33 Tm
서명 / 저자 상온에서 순수 Al 의 static creep 과 cyclic creep 변형시 형성된 전위 구조의 비교 = Comparision of the dislocation structures in cyclically and statically crept pure aluminum at 0.33 Tm / 황우택.
발행사항 [서울 : 한국과학기술원, 1983].
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등록번호

4102307

소장위치/청구기호

학술문화관(문화관) 보존서고

MMS 8332

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초록정보

The characteristics of a dislocation structure in a deformed metal are believed to influence a number of mechanical properties. Depends on the test conditions cyclic creep may accelerate the deformation rate compared to that of static creep. The fact that the creep rate of cyclic creep is faster than that of static creep suggests that there might be conspicuous difference between the dislocation structures of statically and cyclically crept specimens. Unfortunately, little is known quantitatively about the nature of the dislocation structures in the specimens cyclically and statically crept. Because of this cause, the relationship between the creep properties and dislocation structures is our concern. In polycrystalline 99.99% Aluminum, the creep characteristics are compared with dislocation structures produced by cyclic (2cpm, $\frac{t_u}{t_1}$=0.5, 1) and static creep at $0.33T_m$ and under the peak stress of 54Mpa. Transmission electron microscopy was used to study the dislocation structures formed during the creep deformation processes. In the present work, no difference was detected between the cell sizes, but the marked difference was observed in the thickness of cell boundary and the number of dislocations within the cell interior produced under the same peak stress by steady state static and cyclic creep. It is observed that the annihilation of dislocations occurs during cyclic unloading creep (stage). And there is evidence that the recovery by the climb of dislocations occurs during cyclic unloading stage. From these results, it is considered that the recovery process generates mobile dislocations and the movement of glissile dislocations contributes to the cyclic creep acceleration. The activation energy for cyclic creep, $Q_{cy}$=63.5KJ/mole, is lower than that for static creep, $Q_{st}$=88.5KJ/mole. It is suggested that the activation energy for cyclic creep is the activation energy of vacancy migration in pure Aluminum at $0.33T_m$. From the above results, it is considered that cyclic creep acceleration occurs due to the enhanced climb of edge dislocations by excess vacancies during cyclic unloading stage.

서지기타정보

서지기타정보
청구기호 {MMS 8332
형태사항 [iii], 47 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Woo-Taek Hwang
지도교수의 한글표기 : 남수우
지도교수의 영문표기 : Soo-Woo Nam
학위논문 학위논문(석사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 43-46
주제 Dislocations.
Creep.
Metals --Mechanical properties.
Transmission electron microscopy.
전위 (수정) --과학기술용어시소러스
크리프. --과학기술용어시소러스
기계적 성질. --과학기술용어시소러스
전자 현미경 관찰. --과학기술용어시소러스
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