• Title, Summary, Keyword: Particle-Reinforced Metal Matrix Composites

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Wear Characteristics of Particulate Reinforced Metal Matrix Composites Fabricated by a Pressureless Metal Infiltration Process (무가압함침법으로 제조된 입자강화 금속복합재료의 마모특성)

  • 김재동;정순억;김형진
    • Journal of Ocean Engineering and Technology
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    • v.17 no.1
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    • pp.55-60
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    • 2003
  • The effect of size and volume fraction of ceramic particles, with sliding velocity on the wear properties were investigated for the metal matrix composites fabricated by the pressureless infiltration process. The metal matrix composites exhibited about 5.5 - 6 times the wear resistance compared with AC8A alloy at high sliding velocity, and by increasing the particle size and decreasing the volume fraction, the wear resistance was improved. The wear resistance of metal matrix composites and AC8A alloy exhibited different aspects. Wear loss of AC8A alloy increased with sliding velocity, linearly : whereas, metal matrix composites indicated more wear loss than AC8A alloy at the slow velocity region. However, a transition point of wear loss was found at the middle velocity region, which shows the minimum wear loss. Further, wear loss at the high velocity region exhibited nearly the same value as the slow velocity region. In terms of wear mechanism, the metal matrix composites generally exhibited abrasive wear at slow to high sliding velocity; however, AC8A alloy showed abrasive wear at low sliding velocity and adhesive and melt wear at high sliding velocity.

Wear Characteristics of Particulate Reinforced Metal Matrix Composites Fabricated by Pressureless Metal Infiltration Process (무가압함침법으로 제조된 입자강화 금속복합재료의 마모특성)

  • Kim, Jae-Dong;Jung, Sun-Uk;Kim, Hyung-Jin
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • pp.379-384
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    • 2002
  • The effect of size and volume fraction of ceramic particles with sliding velocity on the wear properties were investigated for the metal matrix composites fabricated by pressureless infiltration process. The particulate metal matrix composites exhibited about 5.5 - 6 times of excellent wear resistance compared with AC8A alloy at high sliding velocity, and as increasing the particle size and decreasing the volume fraction the wear resistance was improved. The wear resistance of metal matrix composites and AC8A alloy exhibited different aspects. Wear loss of AC8A alloy increased with sliding velocity linearly. whereas metal matrix composites indicated more wear loss than AC8A alloy at slow velocity region, however a transition point of wear loss was found at middle velocity region which show the minimum wear loss, and wear loss at high velocity region exhibited nearly same value with slow velocity region. In terms of wear mechanism, the metal matrix composites exhibited the abrasive wear at slow to high sliding velocity generally, however AC8A alloy showed abrasive wear at low sliding velocity and adhesive and melt wear at high sliding velocity.

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Strength Analysis of Particle-Reinforced Composites with Length-Scale Effect based on Geometrically Necessary Dislocations (기하적 필수 전위에 의한 길이효과를 고려한 입자 강화 복합재의 강도해석)

  • Suh, Y.S.;Joshi, Shailendra P.;Ramesh, K.T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.322-325
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    • 2009
  • An enhanced continuum model for the size dependent strengthening of particle reinforced composites is presented. The model accounts explicitly for the enhanced strength in a discretely defined "punched zone" around the particle in a metal matrix composite as a result of geometrically necessary dislocations developed through a CTE mismatch. The size of the punched zone presents an intrinsic length scale, and this results in the size dependence of the overall behavior of the composite. Results show that predicted 0.2% offset yield stresses are increasing with smaller inclusions and larger volume fractions and this length-scale effect on the enhanced strength can be observed by explicitly including GND region around the particle.

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Tensile Behavior of Fiber/Particle Hybrid Metal Matrix Composites (섬유/입자 혼합금속복합재료의 인장거동)

  • 정성욱;정창규;한경섭
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.139-142
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    • 2002
  • This study presents a mathematical model predicting the stress-strain behavior of fiber reinforced (FMMCs) and fiber/particle reinforced metal matrix composites (F/P MMCs). MMCs were fabricated by squeeze casting method using Al2O3 short fiber and particle as reinforcement, and A356 aluminum alloy as matrix. The fiber/particle ratios of F/P MMCs were 2:1, 1:1, 1:2 with the total reinforcement volume fraction of 20 vol.%, and the FMMCs were reinforced with 10 vol,%, 15 vol. %, 20 vol. % of fibers. Tensile tests were conducted and compared with predictions which were derived using laminate analogy theory and multi-failure model of reinforcements. Results show that the tensile strength of FMMCs with 10 vol.% of fiber was well matched with prediction, and as the fiber volume increases, predictions become larger than experimental results. The difference between the prediction and experiment is considered to be a result of matrix allowance of fiber damage in tensile loading. As the fiber volume fraction in FMMCs increases, the fiber damage increases and so that the tensile strength is reduced. The strength of F/P MMCs approaches more closely to the prediction than FMMCs reinforced with 20 vol.% of fibers because F/P MMCs contains small quantity of fibers and thus has a positive effect in fiber strengthening.

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Investigation of Reinforced Distribution in Fabrication Process of Metal Matrix Composites by Combined Stirring Process (복합교반법에 의한 금속복합재료의 제조공정에 따른 강화재의 분산성 검토)

  • 이동건;강충길
    • Composites Research
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    • v.14 no.5
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    • pp.1-11
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    • 2001
  • The particulates reinforced metal matrix composites(PMMC) have a number of interesting mechanical properties. including high strength and good resistance to wear at high temperature and low thermal expansion. The equipment structure to obtain the homogeneous distribution in composites are proposed for the continuous pouring of reinforcement at the desired temperature. The particulates reinforced metal matrix composites(A357/SiCp) were fabricated by the process of the combined stirring method with the various fabrication process. The combined stirring method to niform distribution of particle is consisted of two stirring force both electro-magnetic stirring generated from induction heating and mechanical stirring with graphite stirrer. PMMC billets were fabricated with the volume fractions ranged from 0% to 20% and particle sizes ranged from 14${\mu}{\textrm}{m}$ to 25${\mu}{\textrm}{m}$. It is important to cont the size of primary $\alpha$-Al solid particles because it could become the cause of the particle pushing or capture phenomena from the fact that secondary dendrite arm spacing size depends on the cooling rate during the solidification in hypoeutectic Al-Si alloy. Therefore, the effect of primary $\alpha$-Al on the reinforcement distribution in matrix alloys has been investigated. The microstructure of PMMC fabracated with various volume fractions(0%, 10%, and 20%) and particle size were observed.

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High temperature and damping properties of squeeze cast Mg hybrid Metal Matrix Composites. (하이브리드 Mg 복합재료의 진동 감쇠능 및 고온 특성평가)

  • 장재호;김봉룡;최일동;조경목;박익민
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.143-146
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    • 2002
  • Mg alloy is the lightest material of structural materials and is noticed for lightweight automotive parts because of excellent castability, superior ductility and damping capacity than Al alloy. But Mg Alloy is poor corrosion resistance and high temperature creep properties. In this study, Mg Matrix Composites were fabricated by squeeze casting method to improve high temperature creep properties and damping capacity. Hybrid Mg composites reinforced with Alborex, graphite particle, and SiCp was improved creep properties and damping capacity compared with Mg alloy. Compared to the length ($9\mu\textrm{m}, 27\mu\textrm{m}, 45\mu\textrm{m} etc.$), Hybrid Mg composites reinforced with SiCp, one of the most superior of the length and Alborex were more superior than those reinforced with graphite particle and Alborex in mechanical properties, creep characteristics, and damping capacity, etc.

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Investigation of Microstructure Inhomogeneity in SiCp-reinforced Aluminum Matrix Composites

  • Gacsi, Zoltan;Gur, C.Hakan;Makszimus, Andrea;Pieczonka, Tadeusz
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.1303-1304
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    • 2006
  • The type, volume fraction, size, shape and arrangement of embedded particles influence the mechanical properties of the particle reinforced metal matrix composites. This presents the investigation of the SiC particle and porosity distributions in various aluminum matrix composites produced by cold- and hot-pressing. The microstructures were characterized by optical microscopy and stereological parameters. SiC and porosity volume fractions, and the anisotropy distribution function were measured to establish the influence of the consolidation method.

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Effects of Processing Parameters on the Mechanical Properties of Aluminium Matrix Composites (알루미늄 기지 금속복합재료의 기계적 성질에 미치는 제조변수의 영향)

  • Kim, J.D.;Koh, S.W.;Kim, H.J.
    • Journal of the Korea Society For Power System Engineering
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    • v.9 no.4
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    • pp.130-136
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    • 2005
  • The effects of additional Mg content, the size and volume fraction of reinforcement phase on the mechanical properties of ceramic particle reinforced aluminium matrix composites fabricated by pressureless metal infiltration process were investigated. The hardness of $SiC_p/AC8A$ composites increased gradually with an increase in the additive Mg content, while the bending strength of $SiC_p/AC8A$ composites increased with an increase in additive Mg content up to 5%. However, this decreased when the level of additive Mg content was greater than 5% due to the formation of coarse precipitates by excessive Mg reaction and an increase in the porosity level. The hardness and strength of the composites increased with decreasing the size of SiC particle. It was found that the composites with smaller particles enhanced the interfacial bonding than those with bigger particles from fractography of the composites. The hardness of $Al_2O_{3p}/AC8A$ composites increased gradually with an increase in the volume fraction, however, the bending strength of $Al_2O_{3p}/AC8A$ composites decreased when the volume fraction of alumina particle was greater than 40% owing to the high porosity level.

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Numerical Assessment of Dislocation-Punching Theories for Continuum Structural Analysis of Particle-Reinforced Metal Matrix Composites (입자 강화 금속기지 복합재의 연속체 강도해석을 위한 전위 펀칭 이론의 전산적 평가)

  • Suh, Yeong-Sung;Kim, Yong-Bae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.3
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    • pp.273-279
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    • 2011
  • The yield strength of particle-reinforced composites increases as the size of the particle decreases. This kind of length scale has been mainly attributed to the geometrically necessary dislocation punched around the particle as a result of the mismatch of the thermal expansion coefficients of the particle and the matrix when the composites are cooled down after consolidation. In this study, two dislocation-punching theories that can be used in continuum structural modeling are assessed numerically. The two theories, presented by Shibata et al. and Dunand and Mortensen, calculate the size of the dislocationpunched zone. The composite yield strengths predicted by finite element analysis were qualitatively compared with experimental results. When the size of the particle is less than $2{\mu}m$, the patterns of the composite strength are quite different. The results obtained by Shibata et al. are in qualitatively better agreement with the experimental results.

Wear Behavior of Saffil/SiCp reinforced Metal Matrix Composites at the room temperature (Saffil/SiCp을 이용한 금속 복합재료의 상온 마모 거동)

  • 조종인;한경섭
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.46-49
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    • 2003
  • Aluminum based metal matrix composites(MMCs) are well known for their high specific strength, stiffness and hardness. They are gaining further importance because of their high wear resistance. In this study, Al/Saffil-20%, Al/Saffil-5%/Al2O3(particle type)-15% and Al/Saffil-5%/SiC(particle type)-15% hybird MMCs' wear behavior were characterized by the pin-on-disk test under various normal load The superior wear resistance was exhibited at Al/Saffil-5%/SiC(particle type)-15% MMCs. And this MMCs' predominant wear mechanism is subsurface cracking in the low load wear regime. Others(Al/Saffil-20%, Al/Saffil-5%/Al2O3(particle type)-15%) showed the similar wear resistance with each other at the same test condition. In the low load & room temperature condition, the wear resistance was improved due to the high hardness of the ceramic reinforcements. As the test load increased, the wear properties were governed by the wear properties of matrix.

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