서지주요정보
자체 반응 소결에 의한 물라이트-지르코니아 복합체의 기계적 성질에 관한 연구 = A study on in situ-reacted mullite-zirconia composite and its mechanical properties
서명 / 저자 자체 반응 소결에 의한 물라이트-지르코니아 복합체의 기계적 성질에 관한 연구 = A study on in situ-reacted mullite-zirconia composite and its mechanical properties / 오경영.
저자명 오경영 ; Oh, Kyung-Young
발행사항 [서울 : 한국과학기술원, 1985].
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소장정보

등록번호

4103455

소장위치/청구기호

학술문화관(문화관) 보존서고

MMS 8557

SMS전송

도서상태

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초록정보

Mullite/zirconia composite was obtained by $in$ $situ$-reactive sintering of zircon and alumina mixture, and its mechanical properties were studied in conjunction with interpretation of microstructure of this composite. Dissociation of zircon into zirconia and silica and the subsequent reaction of silica with $Al_2O_3$ to form mullite initiated at 1475±10℃, simultaneously. And above 1565℃, no zircon phase was remained in the mixture. Martensitic transformation of zirconia phase thus being dispersed in the composite occurred at 600℃ as a 4-mol% $Y_2O_3$ is added to the content of zirconia. Nucleation and extension of microcrack in this composite were interpreted for the toughening mechanism from the observation of microstructure. On cooling tetragonal (t) to monoclinic (m) phase transformation induced microcrack at the grain-boundary of mullite matrix, which in turn absorbs the fracture energy created in stress field. M.O.R. (4-point) and fracture toughness ($K_{1c}$) of this composite were 250 $MN\cdot{m}^{-2}$ (max. 330) and 3.3 $MN\cdot{m}^{-3/2}$, respectively. The weight fraction of t-$ZrO_2$ being retained at room temperature was 0.33. This t-$ZrO_2$ phase did not transform to m-$ZrO_2$ phase under stress field such as polishing. Therefore, the transformation toughening mechanism was not applicable in this composite. Increasing of M.O.R. and $K_{1c}$ value was insignificant even the weight fraction of t-$ZrO_2$ phase increase 0.12 to 0.33. It was concluded that the toughening mechanism of mullite/zirconia composite was attributed to the grain-boundary strengthening, resulted from a "meta-stable solid solution" in which substitute $Al^{3+}$ and $Si^{4+}$ for $Zr^{4+}$, and $\it{vice versa}$, between mullite matrix and zirconia grains by EPMA.

서지기타정보

서지기타정보
청구기호 {MMS 8557
형태사항 v, 73 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Kyung-Young Oh
지도교수의 한글표기 : 장성도
지도교수의 영문표기 : Sung-Do Jang
학위논문 학위논문(석사) - 한국과학기술원 : 재료공학과,
서지주기 참고문헌 : p. 64-71
주제 Composite materials.
Sintering.
Metals --Mechanical properties.
Phase transformations (Statistical physics)
Fracture toughness.
복합 재료. --과학기술용어시소러스
기계적 성질. --과학기술용어시소러스
반응 소결. --과학기술용어시소러스
상변태. --과학기술용어시소러스
강화. --과학기술용어시소러스
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