• Title, Summary, Keyword: $SiC_{p}$/Al Composites

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High Temperature Deformation Behavior of $SiC_p/Al-Si$ Composites ($SiC_p/Al-Si$ 복합재료의 고온변형 특성)

  • 전정식;고병철;김명호;유연철
    • Transactions of Materials Processing
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    • v.3 no.4
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    • pp.427-439
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    • 1994
  • The high temperature deformation behavior of $SiC_p/Al-Si$ composites and Al-Si matrix was studied by hot torsion test in a range of temperature from $270^{\circ}C$ to $520^{\circ}C$ and at strain rate range of $1.2{\times}10_{-3}~2.16{\times}10_{-1}/sec$. The hot restoration mechanisms for both matrix and composites were found to be dynamic recrystallization(DRX) from the investigation of flow curves and microstructural evolutions. The Si precipitates and SiC particles promoted DRX, and the peak strain$({\varepsilon}_p)$ of the composites was smaller than that of the matrix. Flow stresses of $SiC_p/Al-Si$ composites were found to be generally higher than the matrix, but the difference was quite small at higher temperature due to the decrease of capability of load transfer by SiC particles. With increasing temperature, failure strain of matrix and composites are inclined to increase, the increasing value of failure strain for the $SiC_p/Al-Si$ composites was small compared to that of matrix. The stress dependence of both materials on strain rate() and temperature(T) was examined by hyperbolic sine law, $\.{\varepsilon}=A_1[sinh({\alpha}{\cdot}{\sigma})]_n$exp(-Q/RT)

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Influence of Solidification Condition on the Segregation of SiC Particles in the Al-Si/$SiC_p$ Composites (Al-Si/$SiC_p$ 복합재료에서 SiC의 편석에 미치는 응고 조건의 영향)

  • Kim, Jong-Chan;Kwon, Hyuk-Moo
    • Journal of Korea Foundry Society
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    • v.17 no.2
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    • pp.180-187
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    • 1997
  • The influence of solidification condition on the segregation of SiC particles in the $Al-xSi/6wt%SiC_p$(x: 6, 10, 14, 18${\cdot}$wt%) composites was investigated in the study. The results are as follows: 1) During the counter-gravity unidirectional solidification of $Al-Si/SiC_p$ composites melt, most of the SiC particles are pushed to the top of the casting. 2) The SiC particles pushing in the $Al-Si/SiC_p$ composite melts are not observed, when the interface velocity of melts increases more than 1.41 ${\mu}m/sec$. 3) The SiC particles are entrapped in the interdendrite regions, when the sizes of SiC particles in the $Al-Si/SiC_p$ composites are large than ${\varphi}22{\mu}m$.

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Properties of Al2O3-SiCw Composites Fabricated by Three Preparation Methods (제조방법에 따른 Al2O3-SiCw 복합체의 특성)

  • Lee, Dae-Yeop;Yoon, Dang-Hyok
    • Journal of the Korean Ceramic Society
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    • v.51 no.5
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    • pp.392-398
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    • 2014
  • $Al_2O_3$-SiC composites reinforced with SiC whisker ($SiC_w$) were fabricated using three different methods. In the first, $Al_2O_3-SiC_w$ starting materials were used. In the second, $Al_2O_3-SiC_w$-SiC particles ($SiC_p$) were used, which was intended to enhance the mechanical properties by $SiC_p$ reinforcement. In the third method, reaction-sintering was used with mullite-Al-C-$SiC_w$ starting materials. After hot-pressing at $1750^{\circ}C$ and 30 MPa for 1 h, the composites fabricated using $Al_2O_3-SiC_w$ and $Al_2O_3-SiC_w-SiC_p$ showed strong mechanical properties, by which the effects of reinforcement by $SiC_w$ and $SiC_p$ were confirmed. On the other hand, the mechanical properties of the composite fabricated by reaction-sintering were found to be inferior to those of the other $Al_2O_3$-SiC composites owing to its relatively lower density and the presence of ${\gamma}-Al_2O_3$ and ${\gamma}-Al_{2.67}O_4$. The greatest hardness and $K_{1C}$ were 20.37 GPa for the composite fabricated using $Al_2O_3-SiC_w$, and $4.9MPa{\cdot}m^{1/2}$ using $Al_2O_3-SiC_w-SiC_p$, respectively, which were much improved over those from the monolithic $Al_2O_3$.

Microstructure and Mechanical Properties of P/M Processed 2XXX Al-${SiC}_{p}$ Composites (분말야금방법으로 제조된 2XXX Al-${SiC}_{p}$ 복합재료의 미세조직과 기계적 성질)

  • 심기삼
    • Journal of Korean Powder Metallurgy Institute
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    • v.4 no.1
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    • pp.26-41
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    • 1997
  • The powder metallurgy (P/M) processed 2009 and 2124 Al composites reinforced with SiC particulates were studied by focusing on the effect of consolidation temperature on the microstructural and mechanical Properties. The mechanical properties such as tensile properties and microhardness of the second phases were analysed in relation to the microstructures observed by a SEM and an optical microscope. The in situ fracture process study using SEM showed that the grain refinement and the removal of manganese-containing particles often observed in the 2124 Al-${SiC}_{p}$ composites were important for the improvement of the mechanical properties. This study offers an optimum consolidation temperature for the control of the manganese-containing particles in the 2124 Al-${SiC}_{p}$ composites that yields mechanical properties higher than those of the 2009 Al-${SiC}_{p}$ composites.

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Effect of Process Parameters on Plasma Nitriding Properties of $FeAl/SiC_p$ Composites ($FeAl/SiC_p$ 복합재료의 공정변수에 따른 플라즈마 질화 특성)

  • 박지환;김수방;박윤우
    • Journal of Korean Powder Metallurgy Institute
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    • v.6 no.4
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    • pp.286-293
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    • 1999
  • This study was to analyse the relationship between process parameters of the sintered composite and plasma nitriding properties with pulsed DC plasma. Fe-40at%$SiC_p$ composites of full density were fabricated by hot pressing at 1100~$1150^{\circ}C$. Sintered Fe-40at%Al and Fe-40at%$Al/SiC_p$ alloys were nitrided under pulsed DC plasma. Excellent surface hardness in the FeAl alloys could be obtained by plasma nitriding. ($H_v$ :100gf, diffusion layer : 1100~$1450kg/mm^2$, matrix : 330~$360kg/mm^2$) The wear resistance of $FeAl/SiC_p$ composites were improved about by 4~6times than FeAl and nitrided $FeAl/SiC_p$ were improved about 2 times than $FeAl/SiC_p$ matrix.

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Fabrication and Mechanical Properties of $SiC_p/Al$ Composites by Pressureless Infiltration Technique (무가압침투법에 의한 $SiC_p/Al$ 복합재료의 제조 및 기계적 특성)

  • Jin, H.G.;Oh, M.S.;Kim, Y.S.
    • Journal of the Korea Society For Power System Engineering
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    • v.5 no.4
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    • pp.74-81
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    • 2001
  • The infiltration behavior of molten Al-alloy, microstructures, hardness, and the interfacial reactions of $SiC_p/Al$ composites fabricated by the pressureless infiltration technique were investigated. It was made clear that both the weight fraction of SiC reinforcement and additive Mg content considerably influenced on the infiltration behavior of the molten Al-alloy matrix. Complete infiltration of molten Al-alloy achieved under the conditions that weight fraction of SiC content is more than 30wt%, and additive Mg content is more than 9wt%. Interfacial region of Al-alloy matrix and SiC reinforcement phase, $Mg_2Si$ was formed by the reaction between Mg and SiC. Another reaction product AlN was also formed by the reaction between Al-alloy matrix and gas atmosphere nitrogen.

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Microstructure and Tensile Properties of $SiC_p$-reinforced Aluminum Alloy Composites Fabricated by Die Casting Method (다이캐스팅법에 의해 제조된 SiC 입자강화 알루미늄합금기 복합재료의 미세조직 및 인장특성)

  • Lee, Tae-Won;Lee, Chi-Hwan
    • Journal of Korea Foundry Society
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    • v.17 no.4
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    • pp.385-392
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    • 1997
  • The main objective of this study is to investigate the microstructure and tensile strength of $SiC_p$/Al alloy composites fabricated by die casting method. Die casting was performed using the preheated mold at the pouring temperature range of $620{\sim}750^{\circ}C$ under the pressure of $1,039 kgf/cm^2$. The low speed and a following high injection speed were 0.4 and 2.1 m/s, respectively. The microstructure of $SiC_p$/Al alloy composites fabricated by die casting method was found to be finer than that of composites fabricated by gravity casting. Also, SiC particulates were homogeneously distributed in refined Al matrix due to rapid solidification. The tensile strength of $SiC_p$/Al alloy composites fabricated by die casting method was found to be varied with cast temperature. The maximun tensile strength of $SiC_p$(10 vol.% and 20 vol.%)/Al alloy composites showed 380 MPa at the cast temperature of $750^{\circ}C$ and 363 MPa at the cast temperature of $700^{\circ}C$, respectively.

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Microstructure of Squeeze Cast AC4A $Al/Al_2O_3+SiC_p$ Hybrid Metal Matrix Composite (용탕단조한 AC4A $Al/Al_2O_3+SiC_p$ 하이브리드 금속복합재료의 미세조직과 기계적 성질)

  • Kim, Min-Soo;Cho, Kyung-Mox;Park, Ik-Min
    • Journal of Korea Foundry Society
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    • v.14 no.3
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    • pp.258-266
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    • 1994
  • AC4A $Al/Al_2O_3+SiC_p$ hybrid composites were fabricated by the squeeze infiltration technique. Effect of applied pressure, volume fraction of reinforcement($Al_2O_3$ and SiC) and SiC particle size($4.5{\mu}m$, $6.5{\mu}m$ and $9.3{\mu}m$) on the solidification microstructure of the hybrid composites were examined. Mechanical properties were estimated preliminarly by fractographic observation, hardness measurement and wear test. Results show that the microstructure of the hybrid composites were quite satisfactory, namely revealing relatively uniform distribution of reinforcements and refined matrix. Some aggregation of SiC particle caused by particle pushing was observed especially in the hybrid composites containg in fine particle($4.5{\mu}m$). Refined matrix was attributed to applied pressure and increased nucleation sites with addition of reinforcements. Fractured facet also revealed finer for the hybrid composites possibly due to refined matrix. Hardness and wear resistance increased with volume fraction of reinforcements. For hybrid composites with $9.3{\mu}m$ SiC, hardness was somewhat lower and wear resistance higher than other composites.

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Microstructure and Mechanical Properties of in situ TiCp/Al Composites Fabricated by the Interfacial Reaction between SiC Particles and Liquid Al-Ti Alloy (SiC입자와 Al-Ti합금 용탕간반응에 의한 in situ 생성 TiC입자강화 Al합금복합재료의 조직과 기계적특성)

  • Lim, Suk-Won;Nakata, Hiromichi
    • Journal of Korea Foundry Society
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    • v.17 no.2
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    • pp.170-179
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    • 1997
  • A noble technique has been developed for fabricating in situ formed $TiC_p/Al$ composites. In this process, fairly stable TiC particles were in situ synthesized in liquid aluminum by the interfacial reaction between an Al-Ti melt and SiC, which is a comparatively unstable carbide from the view-point of thermodynamics. It is possible in the present process to generate TiC particles of nearly 1 ${\mu}m$ in diameter, even utilizing SiC of 14 ${\mu}m$ as raw material. However, the dispersion behavior of TiC particles in the matrix depends on the size of the raw material SiC. Decomposing finer SiC makes the dispersion of TiC particles more uniform and the mechanical properties of composites are improved accordingly. The structure of in situ composites and their mechanical properties are affected by the fabrication temperature and the stirring time. It has been found that the most suitable condition for fabrication should be applied depending on the size of the raw material, even if the same kinds of carbide are used. Furthermore, although Al-Ti-Si system intermetallic compounds are detected in a $TiC_p/Al-Si$ composite which is fabricated by conventional melt-stirrng method, these compounds can not be observed in a $TiC_p/Al-Si$ composite made by this in situ production method. Hence the mechanical properties of the in situ $TiC_p/Al-Si$ composite are superior to those of the conventional $TiC_p/Al-Si$ composites.

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Effect of Volume Fraction on Mechanical and Fatigue Crack Growth Properties of SiC Particle Reinforced AL Alloy Composites (체적비가 $SiC_{p}$/AL 복합재료의 기계적 및 피로균열진전 특성에 미치는 영향)

  • Gwon, Jae-Do;An, Jeong-Ju;Mun, Yun-Bae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.4
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    • pp.1301-1308
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    • 1996
  • In order to save the energy and protect the environment, it were studied about ecomaterials with the developed countries as central figure. In the Metal Matrix Composites(MMCs), this trends appeared the development of the MMCs which had excellent mechanical properties in spite of the low volume fraction of reinforcement. Therefore, in this study, fatigue crack growth test, tensile and hardness test were conducted in order to investigate the mechanical and fatigue properties of 5 %, and 10 % $SiC_{p}$/Al composites. As the results, in the tensile and hardness test, tensile strength and hardness increased but fatigue crack growth rate decreased with $SiC_{p}$/Al volume fraction. And in the view of fatigue failured surface through the SEM, fatigue crack initiated around the SiC particle and in low $\Delta{K}$ regions, fatigue creck detoured the SiC particle but crack propagated through the SiC particle in the high $\DeltaK$ regions.