Cu matrix composites reinforced with chopped carbon fiber (CF), which is cost effective and can be well dispersed, are fabricated using electroless plating and hot pressing, and the effects of content and alignment of CF on the thermal properties of CF/Cu composites are studied. Thermal conductivity of CF/Cu composite increases with CF content in the in-plane direction, but it decreases above 10% CF; this is due to reduction of thermal diffusivity related with phonon scattering by agglomeration of CF. The coefficient of thermal expansion decreases in the in-plane direction and increases in the through-plane direction as the CF content increases. This is because the coefficient of thermal expansion of the long axis of CF is smaller than that of the Cu matrix, and the coefficient of thermal expansion of its short axis is larger than that of the Cu matrix. The thermal conductivity is greatly influenced by the agglomeration of CF in the CF/Cu composite, whereas the coefficient of thermal expansion is more influenced by the alignment of CF than the aggregation of CF.

A powder-in-sheath rolling method is applied to the fabrication of a carbon nano tube (CNT) reinforced copper composite. A copper tube with outer diameter of 30 mm and wall thickness of 2 mm is used as sheath material. A mixture of pure copper powder and CNTs with a volume content of 3 % is filled in a tube by tap filling and then processed to an 93.3 % reduction using multi-pass rolling after heating for 0.5 h at 400 oC. The specimen is then sintered for 1h at 500 oC. The relative density of the 3 vol%CNT/Cu composite fabricated using powder in sheath rolling is 98 %, while that of the Cu powder compact is 99 %. The microstructure is somewhat heterogeneous in width direction in the composite, but is relatively homogeneous in the Cu powder compact. The hardness distribution is also ununiform in the width direction for the composite. The average hardness of the composites is higher by 8Hv than that of Cu powder compact. The tensile strength of the composite is 280 MPa, which is 20 MPa higher than that of the Cu powder compact. It is concluded that the powder in sheath rolling method is an effective process for fabrication of sound CNT reinforced Cu matrix composites.

In this study, we investigate the recycling of aluminum-based metal matrix composites(AMCs) embedded with SiC particulates. The microstructure of the AMCs is characterized by X-ray diffraction and scanning electron microscopy. The possibility of recycling the composite scrap is attempted from the melted alloy and SiC particulates by re-melting, holding and solidification in crucibles. The recovery percentage of the matrix alloy is calculated after a number of holding times, 0, 5, 10, 15, 20, 25 and 30 minutes and for different particulate sizes and weight fractions in the Al matrix. The results show that the recovery percentage of the matrix alloy, as well as the time required for maximum recovery of the matrix, is dependent on the size and weight fraction of SiC particulates. In addition, the percentage recovery increases with particulate size but drops with the particulate fraction in the matrix. The time to reach maximum recovery falls rapidly with an increase in particulate size and fraction.

The present study was focused on the synthesis of a dispersed copper matrix composite material by the combination of the mechanical milling and plasma activated sintering processes. The mixed powder was prepared by the combination of the mechanical milling and reduction processes using the copper oxide and titanium diboride powder as the raw material. The synthesized mixed powder was sintered by the plasma activated sintering process. The hardness and electric conductivity of the sintered bodies were measured using micro vickers hardness and four probe method, respectively. The relative density of composite material sintered at showed about 98% of theoretical density. The composite material has a hardness of about 130Hv and an electric conductivity of about 85% IACS. The hardness and electric conductivity of composite material were about 140 Hv and about 45% IACS, respectively.

Warm compaction powder metallurgy was used to produce a Ti3SiC2 particulate reinforced Cu matrix composite. Fabrication parameters and warm compaction behaviors of Cu powder were studied. Based on the optimized fabrication parameters a Cu-based electrical contact material was prepared. Results showed that in expend of some electrical conductivity, addition of Ti3SiC2 particulate increased the hardness, wear resistivity and anti-friction ability of the sintered Cu-base material.

SiC 보강재 표면에 도금된 Cu금속층이 Al/SiC복합재료의 젖음성에 미치는 영향을 검토하였다. 보강재에 대한 금속층의 도금은 무전해도금법을 이용하였으며, Al/SiC 복합재료의 제조는 텅스텐 발열체 진공로의 670˚C~900˚C에서 제조하여 보강재와 기지간의 접촉부위를 촬영하여 젖음성을 측정하였다 젖음성 측정 결과 보강재에 도금된 Cu층은 젖음성을 향상시켰고, 젖음성의 개선은 보강재에 도금된 금속층과 기지간의 반응에 의해 계면에너지를 변화시킴으로서 나타난 결과이며. 반응을 통한 산화피막의 배제도 영향을 미친 것으로 판단된다