• 제목/요약/키워드: SiC 휘스커

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SiC 휘스커 보강 Al 6061 복합재료의 피로균열진전 특성에 관한 기초 연구 (The Basic Study on Fatigue Crack Growth Behavior of SiC Whisker Reinforced Aluminium 6061 Composite Material)

  • 권재도;안정주;김상태
    • 대한기계학회논문집
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    • 제18권9호
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    • pp.2374-2385
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    • 1994
  • SiCw/Al composite material is especially attractive because of their superior specific strength, specific stiffness, corrosion fatigue resistance, creep resistance, and wear resistance compared with the corresponding wrought Al alloy. In this study, Fatigue crack growth behavior and fatigue crack path morphology(FCPM) of SiC whisker reinforced Al 6061 alloy with 25% SiC volume fraction and Al 6061 allay were performed. Result of the fatigue crack growth test sgiwed that fatigue crack growth rate of SiCw/Al 6061 composite was slower than that of Al 6061 matrix therefore it was confirmed that Sic whisker have a excellent fatigue resistance. And Al 6061 matrix had only FCPM perpendicular to loading direction. On the other hand SiCw/Al 6061 composite had three types in fatigue crack path morphology. First type is that both sides FCPM of artificial notch are perpendicular to loading direction. Second type is that a FCPM in artifical notch has slant angle to loading direction and the other side FCPM is perpendicular to loading direction. Third type is that both sides FCPM of notch have slant angle to loading direction. It was considered that this kinds of phenomena were due to non-uniform distribution of SiC whisker and confirmed by SEM observation for fracture mechanism study.

뮬라이트 휘스커의 제조와 특성 (Preparation and Characterization of Mullite Whiskers)

  • 이홍림;심일용;강종봉
    • 한국세라믹학회지
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    • 제41권1호
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    • pp.51-56
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    • 2004
  • $Al(OH)_3$, 비정질 $SiO_2$, $AIF_3$를 출발원료로 기상-고상 반응을 통해 $1100^{\circ}C$의 저온에서 뮬라이트 휘스커를 합성하였다. $800^{\circ}C$ 온도부근에서 협상의 플루오르토파즈의 생성이 관찰되었으며, $1000^{\circ}C$부터 토퓨ㅏ즈의 분해갸 시작되어 $1100^{\circ}C$ 이상의 온도에서는 전량 뮬라이트가 관찰되었다. $1200^{\circ}C$에서 합성된 뮬라이트 휘스커는 성장 방향이 [001] 방향이었으며, 성장방향에 평형한 면은 {110}면이었다. {110}면사이의 면간 거리는 $5.34^{\AA}C$이었으며, 뮬라이트를 이루는 $Al_2O_3$의 함유량은 73.56wt%이었다.

SiC 휘스커 보강 $Al_2$O$_3$-SiC 복합체의 열간특성 (Thermal Characteristics of SiC Whisker Reinforced $Al_2$O$_3$-SiC Composite)

  • 김윤주;나용한
    • 한국세라믹학회지
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    • 제35권1호
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    • pp.1-4
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    • 1998
  • SiC whisker reinforced Al2O3-SiC composite was fabricated by reaction synthesis method whish is cost ef-fective and allows good dispersion of whiskers. Fracture strength at room temperature showed the highest value with 150$0^{\circ}C$ reaction temperature because a lot of SiC whiskers was formed. Fracture strength at 135$0^{\circ}C$ did not show big differences with reaction temperature due to agglomeration of whiskers and formation of sil-icon oxynitride during hot MO(modulus of rupture) test probably promoting grain boundary sliding.

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물라이트의 환원분해 및 탄화법에 의한 $\beta$-SiC 휘스커의 합성 (Synthesis of $\beta$-SiC Whiskers by Decomposition-Carbonization of Mullite)

  • 김종엽;남원식;최상욱
    • 한국세라믹학회지
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    • 제32권10호
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    • pp.1139-1146
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    • 1995
  • $\beta$-SiC whiskers could be formed from a system of mullite-carbon-hydrogen by VLS mechanism at elevated temperatures. It was considered that methane gases were generated from the reaction of hydrogen gases with carbon black, and were reacted with mullite to produce two kinds of gases; silicon suboxide (SiO) and carbon monoxide (CO) of precursors of SiC. With increasing the synthesizing temperature up to 146$0^{\circ}C$, the formation of $\beta$-SiC whisker increased from 0.58 mg/$\textrm{cm}^2$ to 3.98 mg/$\textrm{cm}^2$ on the basis of unit area of carbon block, and the diameters of whiskers had their uniformity due to the reduction in stacking faults.

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콜로이드 혼합법 및 Sol-Gel 법에 의해 제조한 SiC 휘스커 강화 LAS 기지 복합체의 특성 (Characteristics of SiC Whisker-Reinforced LAS Matrix Composites Fabricated by the Mixed Colloidal Route and the Sol-Gel Process)

  • 김광수;장현명;정창주;백용기
    • 한국세라믹학회지
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    • 제28권12호
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    • pp.1012-1018
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    • 1991
  • SiC whisker-reinforced LAS matrix composites were developed by a mixed colloidal processing route. An optimization of processing conditions was made using the zeta potential data of silica, boehmite, and SiC whisker dispersions. Similarly, the SiC whisker-reinforced composites were also fabricated by the conventional sol-gel process using the hydrolysis-condensation reaction of relevant metal alkoxides. The composites fabricated by the mixed colloidal processing route were characterized by a uniform spatial distribution of SiC whisker throughout the matrix. The fracture toughness increased from 1.3 MPa.m1/2 for the LAS specimen to 5.0 Mpa.m1/2 for the hot-pressed composite (95$0^{\circ}C$ and 20 MPa for 20 min) containing 20 wt% SiC whisker. The increase in fracture toughness appears to result mainly from the crack deflection and the crack bridging by whiskers with some additional toughenings from the whisker pullout and the matrix prestressing mechanisms.

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