• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.73-76
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• 2002

This study developed SiC/Al composites for electronic packaging to which reinforcements were added with the volume fractions of 49%, 56% and 63% by the squeeze casting method. 0.8 wt.% of the inorganic binder as well as the $Al_2O_3$ fiber and SiC particles with the volume fraction of 1:10 were added to the SiC/Al composites For the produced SiC/Al composites, the CTEs (coefficients of thermal expansion) were measured from 30 to $300^{\circ}C$ and compared with the FEM numerical simulation to analyze the temperature dependent properties. The experiment showed the CTEs of SiC/Al composites that were intermediate values of those of Rule of Mixture and Turner's Model. The CTEs were close to Turner's Model in the room temperature and approached the Rule of Mixture as the temperature increases. These properties analyzed from the difference of the average stress acting between the matrix and the reinforcements proposed in this study

• 한국주조공학회지
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• 제20권2호
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• pp.89-96
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• 2000

The effects of modification processing on the refinement of primary Si and the wear behavior of hyper-eutectic Al-Si alloys have been mainly investigated. Refining effects of primary Si in Al-17%Si alloy was more efficient than that of B.390 alloy. Optimum condition of getting the finest primary Si microstructure was when AlCuP modifier is added into the melt at $750^{\circ}C$ and held it at $700^{\circ}C$ for 30 minutes. Wear loss in the specimens of as-cast condition decreases as the size of primary Si decreases, in the order of B.390 alloy, B.390 alloy with AlCuP addition, Al-17%Si alloy and Al-17%Si alloy with AlCuP addition. Wear loss in the aged condition of Al-17%Si alloy, B.390 alloy and B.390 alloy with AlCuP addition decreased due to the increase of compressive residual stress in the matrix by the aging treatment. While, wear loss increased in the aged specimens of Al-17%Si alloy with AlCuP addition and Hepworth addition in which compressive residual stress decreases by the aging treatment. Therefore, it is assumed that higher compressive residual stress in the matrix can reduce the wear loss in composite materials such as hyper-eutectic Al-Si alloys.

• 한국주조공학회지
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• 제17권5호
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• pp.480-487
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• 1997

Particle reinforced metal matrix composites(MMCs) via a centrifugal spray-cast deposition(CSD) process were fabricated by injecting second phase particles($Al_2O_3$<40${\mu}m$, W<17.3${\mu}m$) into copper melt on the atomizing disc. Compositing modes were investigated by combining microstructures and mathematical modeling between Cu droplets and the reinforced particles injected. The $Cu/W_P$ powders were shown that the W particles penetrate and get embedded in the Cu droplets. It is considered that the W particles composite preferentially in Cu melt on the atomizing disc. On the other hand, the $Al_2O_3$, particles did not penetrate into the Cu droplets on the atomizing disc but get attached in surface of Cu droplets during the flight. It is considered that the compositing may be attained in the flight distance which the relative velocity between Cu droplet and $Al_2O_3$, particle is maximum. The microstructure of the $Cu/W_P$ and the $Cu/(Al_2O_3)_p$ composite preform was strongly influenced by compositing modes of droplets, and after subsequent deposition it was comprised as it is called the dispersed type and the cell type of microstructure, respectively.

• 대한금속재료학회지
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• 제46권6호
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• pp.382-389
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• 2008

To manufacture Al MMCs, in-situ melt mixing process is used because it is free from contamination, and it makes reinforcements homogeneously dispersed. Large eddy simulation method is used to find the optimum melt mixing condition. At the Re 3000, the most suitable mixing is occurred between Al-Ti and Al- B melts. The in-situ formed $TiB_2$ particles has the size varying from 40 nm to 130 nm, due to the increase of cooling rate, and exhibits a homogeneous dispersion. And the interface between reinforcement and matrix is clean. Both hardness and Young's modulus of this composite are improved with increasing the cooling rate.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2017년도 춘계학술논문요약집
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• pp.100-101
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• 2017

• 동력기계공학회지
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• 제21권4호
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• pp.94-99
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• 2017

Single walled carbon nanotubes were mixed with various metal powders by mechanical ball milling and sintered by spark plasma sintering processes. Two compositional (0.1 and 1 vol%) of the single walled carbon nanotubes were dispersed onto the pure aluminum, 5052 aluminum alloy, pure titanium, Ti6Al4Vanadium alloy, pure copper, and stainless steel 316L. Each composite powders were spark plasma sintered at $600^{\circ}C$ and well synthesized regardless of the matrices. Vickers hardness of the composite materials was measured and they exhibited higher values regardless of the carbon nanotubes composition than those of the pure materials. Moreover, single walled carbon nanotubes reinforced copper matrix composites showed highest enhancement between the other metal matrices system. We believe that low energy mechanical ball milling and spark plasma sintering processes are useful tool for fabricating of the carbon nanotubes-reinforced various metal matrices composite materials. The single walled carbon nanotubes-reinforced various metal matrices composite materials could be used as an engineering parts in many kind of industrial fields such as aviation, transportation and electro technologies etc. However, detail strengthening mechanism should be carefully investigated.

• 대한기계학회논문집
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• 제14권2호
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• pp.407-412
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• 1990

Elastic modulus of unidirectional short fiber composite has theoretically derived with the consideration of Poisson's ratios of matrix and fiber. Unidirectional short fiber composite is modeled as an aggregate of grains developed by Kerner. Under the assumption of extra strain at fiber ends, the strain distribution along the fiber's length is determined, and the elastic modulus is derived from this distribution. For the consideration of effects of Poisson's ratio, Kerner's results for particulate composites are adapted as boundary conditions. The effect of differences in Poisson's ratio of fiber and matrix on elastic modulus is studied. Proposed equation shows a good agreement with experimental data of Halpin and Tock, et al.

• 한국재료학회지
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• 제9권4호
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• pp.419-427
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• 1999

TiNi shape memory alloy was shape memory heat-treated and investigated its mechanical properties with the variation of prestrain. Also 6061 Al matrix composites with TiNi shape memory alloy fiber as reinforcement have been fabricated by Permanent Mold Casting to investigate the microstructures and interface properties. Yield stress of TiNi wire was the most high in the case of before heat-treatment and then decreased as increasing heat-treatment time. In each heat-treatment condition, the yield stress of TiNi wire was not changed with increasing the amount of prestrain. The interface bonding of TiNi/6061Al composite was fine. There was a 2$\mu\textrm{m}$ thickness of diffusion reaction layer at the interface. We could find out that this diffusion reaction layer was made by the mutual diffusion. The diffusion rate from Al base to TiNi wire was faster than that of reverse diffusion and the amount of the diffusion was also a little more than that of reverse.

• 대한기계학회논문집A
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• 제24권5호
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• pp.1146-1154
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• 2000

Fatigue strength of NiAl and Ni$_3$Al particulate reinforced aluminum alloy composites fabricated by the diecasting method was examined at room and elevated temperatures. The results were compared wit h that of SiC particulate reinforced one. The particulate reinforced composites showed some improvement in the static and fatigue strength at elevated temperatures when compared with that of Al alloy. The composites reinforced by intermetallic compound particles showed good fatigue strengths at elevated temperatures especially $Ni_3AI_{p}/Al$ alloy composite showed good fatigue limit up to high temperature of 30$0^{\circ}C$. Adopting intermetallic compound particle as a reinforcement phase, it will be possible to develop MMC representing better fatigue property at elevated temperature.

• Composites Research
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• 제36권6호
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• pp.435-440
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• 2023

본 연구에서는 기존 사용후핵연료(Spent nuclear fuel) 운반/저장 용기에 사용되는 중성자 흡수용 B₄C/Al 복합소재의 열전도도를 개선하기 위해 탄화붕소(B₄C)와 입방정 질화붕소(cBN)를 동시에 강화재로 사용한 알루미늄(Al) 기지 복합소재를 제조하고 평가를 진행하였다. 이를 위해서 교반주조 공정을 통해 복합재 잉곳을 제조하고 이를 압연하여 중성자 흡수용 소재를 성공적으로 제조하였다. 제조된 소재의 평가를 위해 cBN 첨가에 따른 열전도도와 중성자 흡수능 변화를 관찰하였다. 열전도도 측정 결과, B₄C 단일 입자만을 사용한 복합소재 대비 B₄C, cBN을 함께 사용한 복합소재가 동일 체적률 조건 하에서 약 3%의 열전도도 증가가 발생하는 것을 확인하였으며 중성자 흡수 단면적 계산을 통해 중성자 흡수능이 무시할 수 있는 수준으로 저하가 발생하는 것을 확인하였다. 본 연구의 결과를 바탕으로, 중성자 흡수 소재의 새로운 설계 방안을 제시하고 고성능 운반/저장 용기의 개발에 기여할 수 있을 것으로 기대된다.