서지주요정보
중합금속 W-Ni-Fe 합금의 소서변형과 파열에 관한 연구 = Deformation and fracture of W-Ni- Fe heavy alloys
서명 / 저자 중합금속 W-Ni-Fe 합금의 소서변형과 파열에 관한 연구 = Deformation and fracture of W-Ni- Fe heavy alloys / 천길성.
저자명 천길성 ; Churn, Kil-Sung
발행사항 [서울 : 한국과학기술원, 1979].
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소장정보

등록번호

4000740

소장위치/청구기호

학술문화관(문화관) 보존서고

DMS 7901

휴대폰 전송

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초록정보

The deformation and fracture behavior of W-Ni-Fe heavy alloys are investigated. The W content has been varied between 90 and 98 wt.%, while keeping the Ni:Fe weight ratio constant at 1:1. The tungsten grain size has been also varied by prolonged sintering up to 44 h. The tensile specimens have been prepared by usual powder metallurgy techniques. The specimens have been sintered at 1450˚ or 1500℃ in hydrogen. The stress-strain curve for some specimens show, after the yield point, a decrease of the stress, which resembles L$\ddot{u}$ders strain. This discontinuous yield behavior becomes more pronounced with higher W content and smaller tungsten grain size of the specimens. The deformation stress increases with higher W content and smaller tungsten grain size. The deformation stress of all the specimens with varying W content and grain size can be correlated with the average matrix thickness. This result is explained in terms of the dislocation pile-up in the matrix. The specimens are fully densified after 15 min to 1h of sintering. In these specimens, cracks are formed at the interface between the tungsten grains when the grain deformation reaches critical levels during the tension test. The number of these intergranular cracks increases with deformation. The specimens than fracture catastrophically by propagation of the cracks along the grain-matrix interface and through the matrix and tungsten grains. When the specimens are over-sintered for 4 and 8 h, porosity increases to about 2% by formation of large irregular pores. The ductility becomes 0 and the strength also decreases sharply. This result is attributed to the stress concentration at the sharp corners of the pores. Upon further sintering, the porosity decreases again with a recovery of the mechanical properties.

서지기타정보

서지기타정보
청구기호 {DMS 7901
형태사항 vi, 132 p. : 삽도, 사진 ; 26 cm
언어 한국어
일반주기 부록 : 실험자료 총괄표
저자명의 영문표기 : Kil-Sung Churn
지도교수의 한글표기 : 윤덕용
지도교수의 영문표기 : Duk-N. Yoon
학위논문 학위논문(박사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 115-120
주제 Sintering.
Metals --Mechanical properties.
Fracture.
텅스텐. --과학기술용어시소러스
분말 야금. --과학기술용어시소러스
소결. --과학기술용어시소러스
인장. --과학기술용어시소러스
Tungsten alloys.
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