• Title/Summary/Keyword: High Conductivity Copper Alloy

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Study on the Frition Welding Characteristics of Oxygen Free High Conductivity Copper (무산소동의 마찰 용접 특성에 관한 연구)

  • 정호신;소전강
    • Journal of Ocean Engineering and Technology
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    • v.11 no.1
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    • pp.10-15
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    • 1997
  • Copper and its alloy had been used widely because of its pronouncing characteristics on their high thermal and electrical conductivity. Various fusion welding methods, such as SMAW, SAW, GTAW, GMAW, Electroslag welding amd so on are applied to weld copper and its alloy. But fusion welding of copper has so many welding problems. THe most serious problems were poor penetration amd high thermal contration stress due to its high thermal conductivity and porosity could be formed by rapid cooling rate of fusion welding. In order to avoid such fusion welding problems, preheating, peering and heat treatment must be applied to obtain sound weld joint of copper. But preheating induce another welding problem such as grain coarsening of weld heat affected zone. This grain coarsening reduces ductility and strength of weld joint. In this view of point, friction welding of copper is triedm to obtain sound weld joint of copper by reducing metallurgical problems. This study introduced new concept of heat input for evaluating the friction weldability of copper. As a result, weldability of copper could be evaluated by this new concept of heat input.

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Effects of Added Cr Element on the Tensile Strength and Electrical Conductivity of Cu-Fe Based Alloys (Cu-Fe계 합금의 강도 및 전기전도도에 미치는 Cr 원소첨가의 영향)

  • Kim, Dae-Hyun;Lee, Kwang-Hak
    • Korean Journal of Materials Research
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    • v.20 no.2
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    • pp.60-64
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    • 2010
  • This study looked at high performance copper-based alloys as LED lead frame materials with higher electrical-conductivity and the maintenance of superior tensile strength. This study investigated the effects on the tensile strength, electrical conductivity, thermal softening, size and distribution of the precipitation phases when Cr was added in Cu-Fe alloy in order to satisfy characteristics for LED Lead Frame material. Strips of the alloys were produced by casting and then properly treated to achieve a thickness of 0.25 mm by hot-rolling, scalping, and cold-rolling; mechanical properties such as tensile strength, hardness and electrical-conductivity were determined and compared. To determine precipitates in alloy that affect hardness and electrical-conductivity, electron microscope testing was also performed. Cr showed the effect of precipitation hardened with a $Cr_3Si$ precipitation phase. As a result of this experiment, appropriate aging temperature and time have been determined and we have developed a copper-based alloy with high tensile strength and electrical-conductivity. This alloy has the possibility for use as a substitution material for the LED Lead Frame of Cu alloy.

Analysis of Microstructures and Defects of the Thixoformed Cu rotor for High Efficiency Electrical Motors (반응고 성형법에 의해 제조된 고효율 전동기용 Cu-Rotor의 미세조직 및 결함 분석)

  • 강병무;서동우;손근용;이상용
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10a
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    • pp.55-59
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    • 2003
  • Rotor in small-medium induction motor has been usually manufactured by aluminum diecasting. In order to improve efficiency of induction motors, however, it is desirable that pure aluminum is replaced by high electrical conductivity copper alloy. For this purpose, a rotor is thixoformed with Cu-Ca alloy. Thermomechanical processing(TMP) is carried out to modify the semi-solid microstructure of the alloy and final microstructures and filling defects of thixoformed Cu- rotors are investigated. The characteristics of thixoformed Cu-rotor such as motor efficiency and torque are compared with those of Al rotor.

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Ultra High Conductivity Diamond Composites

  • Bollina, Ravi;Stoiber, Monika
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.922-923
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    • 2006
  • Thermal management is one of the critical aspects in the design of highly integrated microelectronic devices. The reliability of electronic components is limited not only to operating temperature but also by the thermal stresses caused during the operation. The need for higher power densities calls for use of advanced heat spreader materials. A copper diamond composite has been developed with high thermal conductivity $(\lambda)$ and tailorable coefficient of thermal expansion (CTE). Copper diamond composites are processed via gas pressure assisted infiltration with different copper alloys. Emphasis has been placed on the addition of trace elements in deisgning the copper alloys to facilitate a compromise between thermal conductivity and mechanical adhesion. The interfaces between the alloy and the diamond are related to the thermal properties of these copper composites.

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Preparation of $TiB_2$ Dispersed Cu Alloy by Spark Plasma Sintering

  • Kim, Kyong-Ju;Lee, Gil-Geun;Park, Ik-Min
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.523-524
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    • 2006
  • The $TiB_2$ dispersion strengthened copper alloy was attracted as thermal and electrical functional material for the high mechanical strength, high thermal stability and good conductivity of $TiB_2$. In the present study, the focus is on the synthesis of $TiB_2$ dispersed copper alloy by spark plasma sintering process using copper oxide and titanium diboride as raw materials. The mechanical, thermal and electrical properties of sintered bodies were discussed with the sintering parameters, and developed microstructure and phase of sintered bodies.

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Effects of Copper and Copper-Alloy on Friction and Wear Characteristics of Low-Steel Friction Material (로우스틸 마찰재의 마찰 및 마모특성에 미치는 구리계 재료의 영향)

  • Jung, Kwangki;Lee, Sang Woo;Kwon, Sungwook;Choi, Sungwoo;Lee, Heeok
    • Tribology and Lubricants
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    • v.36 no.4
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    • pp.207-214
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    • 2020
  • In this study, we investigated the effects of copper and copper-alloy on the frictional and wear properties of low-steel friction material. The proportions of copper and copper-alloy in the brake friction materials used in passenger cars are very high (approximately 5-20% weight), and these materials have significant effects on friction and wear characteristics. In this study, the effects of cupric ingredients, such as the copper fiber and brass fiber, are investigated using the friction materials based on commercial formulations. After the copper and brass fibers from the same formulation were removed, the frictional and wear characteristics were evaluated to determine the influence of the copper and copper-alloy. We evaluated the frictional and wear characteristics by simulating various braking conditions using a 1/5 scale dynamometer. The results show that the friction material containing copper and brass fibers have excellent frictional stability and a low wear rate compared to the friction material that does not contain copper and brass fibers. These results are attributed to the excellent ductility, moderate melting point, high strength, and excellent thermal conductivity of copper and copper-alloy. We analyzed the surfaces of the friction materials before and after the performing the friction tests using a scanning electron microscope-energy dispersive X-ray spectroscope, confocal microscope, and roughness tester to verify the frictional behavior of copper and copper-alloy. In future studies, it will be applied to the development of copper-free friction materials based on the results of this study.

Investigation of shielding effects of 60Hz ELF magnetic fields on shielding material property (차폐재의 재료특성에 따른 60Hz ELF 자계차폐 효과분석)

  • Min, Suk-Won;Song, Ki-Hyun;Myung, Sung-Ho
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1960-1962
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    • 2004
  • In this paper, we have studied shielding characteristics of high conductivity or high permeability materials on ELF magnetic fields generated from single or three phase AC line. Perm alloy has been selected as high permeability material and copper as high conductivity material. Four-plate shield (square section) was considered as a shielding shape. We found copper showed stable shielding effects more than perm alloy.

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The study of drawing on the heterogeneous materials for the unidirectional alignment of carbon nanofiber in metal matrix nanocomposite (금속기지 나노복합재용 탄소나노섬유 일방향 배열을 위한 이종재 인발 연구)

  • 백영민;이상관;엄문광;김병민
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10a
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    • pp.301-301
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    • 2003
  • In current study, Nanocomposites are reinforced with carbon nanofiber, carbon nanotube and SiC, etc. Since the nano reinforcements have the excellent mechanical, thermal and electrical properties compared with that of existing composites, it has lately attracted considerable attention in the various areas. Cu have been widely used as signal transmission materials for electrical electronic components owing to its high electrical conductivity. However, it's size have been limited to small ones due to its poor mechanical properties. Until now, strengthening of the copper alloy was obtained either by the solid solution and precipitation hardening by adding alloy elements or the work hardening by deformation process. Adding the alloy elements lead to reduction of electrical conductivity. In this aspect, if carbon nanofiber is used as reinforcement which have outstanding mechanical strength and electric conductivity, it is possible to develope Cu matrix nanocomposite having almost no loss of electric conductivity. It is expected to be innovative in electric conducting material market. The unidirectional alignment of carbon nanofiber is the most challenging task developing the cooer matrix composites of high strength and electric conductivity. In this study, the unidirectional alignment of carbon nanofibers which is used reinforced material are controlled by drawing process and align mechanism as well as optimized drawing process parameter are verified via numerical analysis. The materials used in this study were pure copper and the nanofibers of 150nm in diameter and of 10∼20$\mu\textrm{m}$ in length. The materials have been tested and the tensile strength was 75MPa with the elongation of 44% for the copper. it is assumed that carbon nanofiber behave like porous elasto-plastic materials. Compaction test was conducted to obtain constitutive properties of carbon nanofiber Optimal parameter for drawing process was obtained by analytical and numerical analysis considering the various drawing angles, reduction areas, friction coefficient, etc. The lower drawing angles and lower reduction areas provides the less rupture of co tube is noticed during the drawing process and the better alignment of carbon nanofiber is obtained.

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Thermal Properties and Microstructural Changes of Fe-Co System Valve Seat Alloy by High Densification Process (고밀도화 공정에 의한 Fe-Co 계 밸브시트 합금의 조직변화와 열적 특성)

  • Ahn, In-Shup;Park, Dong-Kyu;Ahn, Kwang-Bok;Shin, Seoung-Mok
    • Journal of Powder Materials
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    • v.26 no.2
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    • pp.112-118
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    • 2019
  • Infiltration is a popular technique used to produce valve seat rings and guides to create dense parts. In order to develop valve seat material with a good thermal conductivity and thermal expansion coefficient, Cu-infiltrated properties of sintered Fe-Co-M(M=Mo,Cr) alloy systems are studied. It is shown that the copper network that forms inside the steel alloy skeleton during infiltration enhances the thermal conductivity and thermal expansion coefficient of the steel alloy composite. The hard phase of the CoMoCr and the network precipitated FeCrC phase are distributed homogeneously as the infiltrated Cu phase increases. The increase in hardness of the alloy composite due to the increase of the Co, Ni, Cr, and Cu contents in Fe matrix by the infiltrated Cu amount increases. Using infiltration, the thermal conductivity and thermal expansion coefficient were increased to 29.5 W/mK and $15.9um/m^{\circ}C$, respectively, for tempered alloy composite.

Effects of Cr content and Thermomechanical Treatment on Tensile Strength and Electrical Conductivity of Cu-Cr Alloys (Cu-Cr 합금의 인장강도와 전기전도도에 미치는 Cr 첨가량 및 가공열처리의 영향)

  • Kim, Ki-Tae;Jung, Woon-Jae;Shin, Han-Chul;Choi, Chong-Sool
    • Journal of the Korean Society for Heat Treatment
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    • v.14 no.1
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    • pp.17-21
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    • 2001
  • The effects of Cr content above its solubility limit and thermomechanical treatment on tensile strength and electrical conductivity of Cu-Cr alloys were studied to obtain optimum Cr content exhibiting a high tensile strength without degradation of electrical conductivity. The increase in Cr content above the solubility limit increased tensile strength of Cu-Cr alloys without deterioration of the electrical conductivity. The electrical conductivity was not affected by cold rolling. The electrical conductivity of a Cu-3.5%Cr alloy subjected to cold rolling ${\rightarrow}$ aging treatment ($450^{\circ}C{\times}1hr$) ${\rightarrow}$ cold rolling was equal to that of the alloy subjected to cold rolling ${\rightarrow}$ aging treatment. However, the tensile strength of the alloy subjected to the former thermomechanical treatment was superior to that of the alloy subjected to the latter thermomechanical treatment at all the deformation degrees.

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