• Proceedings of the KSME Conference
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• 2001.06a
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• pp.383-388
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• 2001

Effects of particle property variation of cone crack shape according to impact velocity in silicon carbide materials were investigated. The damage induced by spherical impact having different material and size was different according to materials. The size of ring cracks induced on the surface of specimen increased with increase of impact velocity within elastic contact conditions. The impact of steel particle produced larger ring cracks than that of SiC particle. In case of high impact velocity, the impact of SiC particle produced radial cracks by the elastic-plastic deformation at impact regions. Also percussion cone was formed from the back surface of specimen when particle size become large and its impact velocity exceeded a critical value. Increasing impact velocity, zenithal angle of cone cracks in SiC material was linearly decreasing not effect of impact particle size. An empirical equation, $\theta=\theta_{st}-\upsilon_p(180-\theta_{st})(\rho_p/\rho_s)^{1/2}/415$, was obtained from the test data as a function of quasi-static zenithal angle of cone crack($\theta_{st}$), the density of impact particle(${\rho}_p$) and specimen(${\rho}_s$). Applying this equation to the another materials, the variation of zenithal angle of cone crack could be predicted from the particle impact velocity.

• Transactions of Materials Processing
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• v.15 no.6 s.87
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• pp.421-427
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• 2006

Drawing process of Al-1%Si bonding wire considering fine Si particle is analyzed in this study using FE-simulation. Al-1%Si boding wire requires electric conductivity because Al-1%Si bonding wire is used for interconnection in semiconductor device. About 1% of Si is added to Al wire for dispersion-strengthening. Distribution and shape of fine Si particle have strongly influence on the wire drawing process. In this study, therefore, the finite-element model based on the observation of wire by continuous casting is used to analyze the effect of various parameters, such as the reduction in area, the semi-die angle, the aspect ratio, the inter-particle spacing and orientation angle of the fine Si particle on wire drawing processes. The effect of each parameter on the wire drawing process is investigated from the aspect of ductility and defects of wire. From the results of the analysis, it is possible to obtain the important basic data which can be guaranteed in the fracture prevention of Al-1 %Si wire.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.05a
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• pp.72-72
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• 1997

• Journal of Korea Foundry Society
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• v.13 no.5
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• pp.450-461
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• 1993

AC4C alloy casts in the metallic mold, zircon sand mold, silica sand mold and shell mold with the pouring temperatures of 680, 710 and $740^{\circ}C$ have been investigated. The tensile strength, elongation and hardness of AC4C alloy castings have been influenced by the kind of molds used. The mechanical properties in zircon sand mold castings were greater than those in other sand mold castings, but were inferior to the properties in metallic mold castings. Eutectic Si particle size and DAS were increased in the order of metallic mold, ziron sand mold, silica sand mold and shell mold. Also, they were increased with the increase of pouring temperatures. DAS, eutectic Si particle size and grain size decreased with the increase of mechanical properties as the cooling rate increased. The eutectic Si particle size and DAS of AC4C alloy castings after T6 treatment were decreased in as-cast. The variation of eutectic Si particle size has been effected on the tensile strength, elongation and fractured surface.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.139-142
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• 2000

The SiCp/AC8A composites were fabricated by the pressureless metal infiltration process successfully. The effect of additional Mg, which were mixed with SiC particles to promote interfacial wetting between the reinforcement and matrix alloy, and particle size on the mechanical properties was investigated. By increasing the additional Mg content the hardness of SiCp/AC8A composites was increased due to the hard reaction products, but the bending strength was decreased by the excess reaction of Mg and high porosity level when the additional Mg content is over 7%. The Hardness and bending strength was increased by decreasing the size of SiC particle.

• Composites Research
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• v.22 no.3
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• pp.74-81
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• 2009

Reversed plane bending fatigue tests were conducted on SiC particle reinforced and SiC whisker reinforced aluminum composite. The initiation and growth behaviors of small surface fatigue cracks were continuously monitored by the replica technique and the causes of fracture and fracture mechanism were investigated by SEM. The relationship between da/dn and $K_{max}$ show that da/dn increases in high stress level while decrease and again increases with increasing of $K_{max}$ in low stress level for two materials.

• Journal of the Korean Ceramic Society
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• v.53 no.6
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• pp.581-596
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• 2016

A comprehensive review on sliding and solid particle erosion wear characteristics of silicon carbide (SiC) ceramics and SiC composites is provided. Sliding or erosion wear behavior of ceramics is dependent on various material characteristics as well as test parameters. Effects of microstructural and mechanical properties of SiC ceramics are particularly focused to understand tribological performance of SiC ceramics. Results obtained between varieties of pairs of SiC ceramics indicate complexity in understanding dominant mechanisms of material removal. Wear mechanisms during sliding are mainly divided in two groups as mechanical and tribochemical. In solid particle erosion conditions, wear mechanisms of SiC ceramics are explained by elastic-plastic deformation controlled micro-fracture on the surface followed by radial-lateral crack propagation beneath the plastic zone.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.410-415
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• 2013

$ZrB_2$-SiC ceramics are fabricated via hot pressing with different ratios of submicron or nano-sized SiC in a $ZrB_2$-20 vol%SiC system, in order to examine the effect of the SiC size ratio on the microstructures and physical properties, such as thermal conductivity, hardness, and flexural strength, of $ZrB_2$-SiC ceramics. Five different $ZrB_2$-SiC ceramics ($ZrB_2$-20 vol%[(1-x)SiC + xnanoSiC] where x = 0.0, 0.2, 0.5, 0.8, 1.0) are prepared in this study. The mean SiC particle sizes in the sintered bodies are highly dependent on the ratio of nano-sized SiC. The thermal conductivities of the $ZrB_2$-SiC ceramics increase with the ratio of nano-sized SiC, which is consistent with the percolation behavior. In addition, the $ZrB_2$-SiC ceramics with smaller mean SiC particle sizes exhibit enhanced mechanical properties, such as hardness and flexural strength, which can be explained using the Hall-Petch relation.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.237-239
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• 2002

The effect of particle sizes of the metal matrix composites containing 10 wt.%SiCp was investigated with using various tools. The results showed that tool life decreased considerably with increasing particle size and cutting speed. The wear resistance of TiC-coated tools was considerably higher than that of the other tools. It was observed that abrasive wear was the main responsible mechanism for wear of the tool thermal cracks were at high speed while a built-edge formation was also evident at lower speed.

• Journal of Korea Foundry Society
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• v.20 no.5
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• pp.300-306
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• 2000

The objective of this work was to investigate the effects of SiC particle size(50, 100 ${\mu}m$) and additional elements such as Si, Cu and Ti on aging behavior in Al-5Mg-X(Si,Cu,Ti)/SiCp composites fabricated by pressureless infiltration method using hardness and wear test, scanning electron microscopy(SEM) and differential scanning calorimetry(DSC). The peak aging time in Al-5Mg-X(Si, Cu, Ti)/SiCp(50, 100 ${\mu}m$) composites is shorter than Al-5Mg-0.3Si alloy.The peak aging time of 50 ${\mu}m$ SiC particle reinforced Al-5Mg-X(Si,Cu,Ti) composites is shorter than those of 100 ${\mu}m$ SiC particle reinforced of Al-5Mg-X(Si,Cu,Ti) composites. The Al-5Mg-0.3Si-0.1Cu-0.1Ti/SiCp(50 ${\mu}m$) composites aged at $180^{\circ}C$ has higher hardness and better wear resistance than any other aged composite.The aging effect is promoted by the addition of Si and Cu in Al-5Mg/SiCp composites, so the wear resistance of Al-5Mg/SiCp composites with Si and Cu elements is enhanced by the aging treatment.