서지주요정보
W-Ni-Fe heavy-alloy 에서 조성, 성형압력 및 텅크스텐 입자크기가 소결중 밀도화에 미치는 영향 = The effect of tungsten power size, compacting pressure and composition on densification during sintering of W-Ni-Fe heavy-alloy
서명 / 저자 W-Ni-Fe heavy-alloy 에서 조성, 성형압력 및 텅크스텐 입자크기가 소결중 밀도화에 미치는 영향 = The effect of tungsten power size, compacting pressure and composition on densification during sintering of W-Ni-Fe heavy-alloy / 천길성.
저자명 천길성 ; Churn, Kil-Sung
발행사항 [서울 : 한국과학기술원, 1976].
Online Access 원문보기 원문인쇄

소장정보

등록번호

4000192

소장위치/청구기호

학술문화관(문화관) 보존서고

MMS 7623

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

Densification of W-Ni-Fe heavy-alloy during sintering at 1300℃ and 1450℃ was studied. The (Ni + Fe) content of the specimens were 3.5, 10, and 15 weight % while Ni:Fe ratio was maintained at 7:3. Two grades of tungsten powder with average particle size of 1.23μ and 5.4μ were used. In order to observe the effect of compacting pressure on densification rate, the specimens were pressed at 0.5, 2.5, and 5 tons/㎠. During sintering at 1450℃ with some liquid phase present the specimens with small tungsten powder showed faster densification initially. However, after 30 minutes of sintering densities exceeding 99% of the theoretical density were obtained with 1.23 and 5.4 μ tungsten powders. The densification rate was little affected by the (Ni + Fe) content. For the specimen with 3.5%(Ni + Fe) and 1.23 μ W powder compacted at different pressures same high density was obtained in short sintering time for all specimens when sintered at 1450℃. The densification rate at 1300℃ is shown to be greatly affected by the tungsten particle size. After sintering for 60minutes at 1300℃, the specimens with 1.23 μ W-powder are densified to about 98% of the theoretical density, while the specimens with 5.4 μ W-powder show densities around 70-80% of the theoretical density. It is therefore concluded that in liquid phase sintering the tungsten powder size is not critical for obtaining densities approaching the theoretical density, but in solid state sintering it is necessary to use small tungsten powder size to obtain high densification. The fractional volume changes during liquid phase sintering plotted against sintering time in log-log scale show slopes ranging between 0 and 1/5, and varying slightly with composition. This result is inconsistent with any predictions based on Kingery's model of liquid phase sintering. The observed densification rates during solid state sintering cannot be explained by the activated sintering model of Brophy et al. It is suggested that the densification rate should be dependent on the amount of porosity remaining and therefore the "impingement" effect has to be taken into account in establishing a theoretical model for densification during sintering. Observations of the tungsten grain growth show that with smaller (Ni + Fe) content, the tungsten grain growth is considerably larger.

서지기타정보

서지기타정보
청구기호 {MMS 7623
형태사항 vi, 67 p. : 삽도 ; 26 cm
언어 한국어
일반주기 부록 : A, 로 제작 및 제원. - B, Accumulated sintering 과 continuous sintering 방법에 의하여 얻어진 소결 밀도 비교. - C, 오차 계산
저자명의 영문표기 : Kil-Sung Churn
지도교수의 한글표기 : 윤덕용
지도교수의 영문표기 : Duk-Nong Yoon
학위논문 학위논문(석사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 51-54
주제 Tungsten alloys.
Sintering.
Density.
텅스텐 합금. --과학기술용어시소러스
소결 합금. --과학기술용어시소러스
밀도. --과학기술용어시소러스
성형 (조작) --과학기술용어시소러스
중합금.
Densification.
QR CODE qr code