Ceramic particles reinforced copper matrix composites manufactured by advanced powder metallurgy:preparation, performance, and mechanisms

Copper matrix composites doped with ceramic particles are known to effectively enhance the mechanical properties,thermal expansion behavior and high-temperature stability of copper while maintaining high thermal and electrical conductivity.This greatly expands the applications of copper as a functional material in thermal and conductive components,including electronic packaging materials and heat sinks,brushes,integrated circuit lead frames.So far,endeavors have been focusing on how to choose suitable ceramic components and fully exert strengthening effect of ceramic particles in the copper matrix.This article reviews and analyzes the effects of preparation techniques and the characteristics of ceramic particles,including ceramic particle content,size,morphology and interfacial bonding,on the diathermancy,electrical conductivity and mechanical behavior of copper matrix composites.The corresponding models and influencing mechanisms are also elaborated in depth.This review contributes to a deep understanding of the strengthening mechanisms and microstructural regulation of ceramic particle reinforced copper matrix composites.By more precise design and manipulation of composite microstructure,the comprehensive properties could be further improved to meet the growing demands of copper matrix composites in a wide range of application fields.

Fabrication of superaligned carbon nanotubes reinforced copper matrix laminar composite by electrodeposition

A new kind of laminar metal matrix nanocomposite（MMC） was fabricated by an electrodeposition process with copper and superaligned carbon nanotubes film（SACNT film）.The SACNT film was put on a titanium plate and then a layer of copper was electrodeposited on it.By repeating the above process,the laminar Cu/SACNT composite which contains dozens or hundreds of layers of copper and SACNT films was obtained.The thickness of a single copper layer was controlled by adjusting the process parameter easily and the thinnest layer is less than 2 μm.The microscopic observation shows that the directional alignment structure of SACNT is retained in the composite perfectly.The mechanical and electrical properties testing results show that the tensile and yield strengths of composites are improved obviously compared with those of pure copper,and the high conductivity is retained.This technology is a potential method to make applicable MMC which characterizes high volume fraction and directional alignment of carbon nanotubes.

Effects of rare earth element lanthanum on the microstructure of copper matrix diamond tool materials

Effects of rare earth element La on the microstructure of Cumatrix diamond tools were researched under the conditions of variousmaterials components and the process parameters in order to improvematerials properties. SEM, XPS and X-ray were used to investigate thefracture section, microstructure and the element valence inmaterials. The Results shown that the combination of rare earthelement La and transition element Ti is advantageous to the bondingstate Between diamond particles and matrix, so it can improve thematerials properties. Suitable sintering temperature is 790 deg. C.

Fabrication and thermal conductivity of copper matrix composites reinforced by tungsten-coated carbon nanotubes

Carbon nanotubes （CNTs） were coated by tungsten using metal organic chemical vapor deposition. Magnetic stirring was employed to disperse the W-coated CNTs （W-CNTs） in a Cu matrix, and then, the mixed powders were consolidated by spark plasma sintering. The W-CNTs obtained a uniform dispersion within the Cu matrix when the W-CNT content was less than 5.0vo1%, but high content of W-CNTs （10vol%） resulted in the presence of clusters. The W-CNT/Cu composites containing low content of W-CNTs （〈5.0vol%） exhibited a higher thermal conductivity than the sintered pure Cu, while the CNT/Cu composites exhibited no increase in thermal conductivity after the incorporation of uncoated CNTs. The W-CNT content was found to play a crucial role in determining the thermal conductivity of the W-CNT/Cu composites. The thermal conductivity of the W-CNT/Cu composites increased first and then decreased with the W-CNT content increasing. When the W-CNT content was 2.5vo1%, the W-CNT/Cu composite obtained the maximum value of thermal conductivity. The thermal resistance of the （W-CNT）-Cu interface was predicted in terms of Maxwell-Gamett effective medium approximation, and its calculated value was about 3.0× 10-9 m2.K.W-l.

Improving effect of carbonized quantum dots(CQDs)in pure copper matrix composites

Carbon quantum dots(CQDs),which contain a core structure composed of sp^(2)carbon,can be used as the reinforcing phase like graphene and carbon nanotubes in metal matrix.In this paper,the CQD/Cu composite material was prepared by powder metallurgy method.The composite powder was prepared by molecular blending method and ball milling method at first,and then densified into bulk material by spark plasma sintering(SPS).X-ray diffraction,Raman spectroscopy,infrared spectroscopy,and nuclear magnetic resonance were employed to characterize the CQD synthesized under different temperature conditions,and then CQDs with a higher degree of sp^(2)were utilized as the reinforcement to prepare composite materials with different contents.Mechanical properties and electrical conductivity results show that the tensile strength of the 0.2 CQD/Cu composite material is~31%higher than that of the pure copper sample,and the conductivity of 0.4 CQD/Cu is~96%IACS,which is as high as pure copper.TEM and HRTEM results show that good interface bonding of CQD and copper grain is the key to maintaining high mechanical and electrical conductivity.This research provides an important foundation and direction for new carbon materials reinforced metal matrix composites.

Microstructure and properties of copper matrix composites reinforced by nano-SiC and nano-Al_2O_3 particles

Copper/silicon carbide composites （Cu/SiC） and copper/alumina composites （Cu/Al2O3） were fabricated by the powder metallurgy method. The influence of reinforcement particles contents on the relevant properties of the composites and the microstructure of Cu/SiC and Cu/Al2O3 composites were studied. The reinforcement effects of nano-SiC and nano-Al2O3 particles were compared. The experimental results show that with the increase of the amount of nano-SiC and nano-Al2O3 particles, the density of the both composites decreases, the resistivity increases, whereas the hardness increases firstly and then drops. The softening temperatures of the composites are above 700℃ which is far higher than that of the pure copper, leading to the improvement of the thermal stability of the composites at high temperatures. Considering all factors, the reinforcement effects of nano-SiC are better than those of nano-Al2O3 when their contents are the same in the copper matrix.

Synergistic regulation of current-carrying wear performance of resin matrix carbon brush composites with tungsten copper composite powder

Resin matrix carbon brush composites(RMCBCs)are critical materials for high-powered electric tools.However,effectively improving their wear resistance and heat dissipation remains a challenge.RMCBCs prepared with flake graphite powders that were evenly loaded with tungsten copper composite powder(RMCBCs-W@Cu)exhibited a low wear rate of 1.63 mm^(3)/h,exhibiting 48.6%reduction in the wear rate relative to RCMBCs without additives(RMCBCs-0).In addition,RMCBCs-W@Cu achieved a low friction coefficient of 0.243 and low electric spark grade.These findings indicate that tungsten copper composite powders provide particle reinforcement and generate a gradation effect for the epoxy resin(i.e.,connecting phase)in RMCBCs,which weakens the wear of RMCBCs caused by fatigue under a cyclic current-carrying wear.

Thermo-physical Properties of Continuous Carbon Fiber Reinforced Copper Matrix Composites

Continuous carbon fiber reinforced copper matrix composites with 70%(volume fraction) of carbon fibers prepared by squeeze casting technique have been used for investigation of the coefficient of thermal expansion(CTE) and thermal conductivity.Thermo-physical properties have been measured in both,longitudinal and transversal directions to the fiber orientation.The results showed that Cf/Cu composites may be a suitable candidate for heat sinks because of its good thermo-physical properties e.g.the low CTE(4.18×10-6/K) in longitudinal orientation and(14.98×10-6/K) in transversal orientation at the range of 20-50℃,a good thermal conductivity(87.2 W/m·K) in longitudinal orientation and(58.2 W/m·K) in transversal orientation.Measured CTE and thermal conductivity values are compared with those predicted by several well-known models.Eshelby model gave better results for prediction of the CTE and thermal conductivity of the unidirectional composites.

Significant strengthening of copper-based composites using boron nitride nanotubes

Nanotubes, such as boron nitride nanotubes (BNNTs) and carbon nanotubes (CNTs), exhibit excellent mechanical properties. In this work, high-quality BNNTs were synthesized by ball milling and annealing. Subsequently, well-dispersed 3vol%BNNTs/Cu and 3vol%CNTs/Cu composites were successfully prepared using ball milling, spark plasma sintering, and followed by hot-rolling. Moreover, the mechanical properties and strengthening mechanisms of BNNTs/Cu and CNTs/Cu composites were compared and discussed in details. At 293 K,both BNNTs/Cu and CNTs/Cu composites exhibited similar ultimate tensile strength (UTS) of~404 MPa, which is approximately 170%higher than pure Cu. However, at 873 K, the UTS and yield strength of BNNTs/Cu are 27%and 29%higher than those of CNTs/Cu, respectively.This difference can be attributed to the stronger inter-walls shear resistance, higher thermomechanical stability of BNNTs, and stronger bonding at the BNNTs/Cu interface as compared to the CNTs/Cu interface. These findings provide valuable insights into the potential of BNNTs as an excellent reinforcement for metal matrix composites, particularly at high temperature.

<i>In Situ</i>Analysis of Copper Alloys by Femtosecond Laser Ablation Inductively Coupled Plasma Mass Spectrometry: Constrains on Matrix Effects

Direct analysis of copper-base alloys using laser ablation techniques is an increasingly common procedure in cultural heritage studies. However, main discussions remain focused on the possibility of using non-matrix matched external reference materials. To evaluate the occurrence of matrix effects during in situ microanalysis of copper-base materials, using near infrared femtosecond laser ablation techniques (NIR fs-LA-ICP-MS), two bronzes, i.e., (Sn-Zn)-ternary and (Sn)-binary copper-matrix reference materials, as well as a reference synthetic glass (NIST-SRM-610) have been analyzed. The results have been compared to data obtained on a sulfide-matrix reference material. Similar values in relative sensitivity averages of 63Cu, 118Sn and 66Zn, as well as in 118Sn/63Cu and 66Zn/63Cu ratios were obtained, for all analyzed matrix types, i.e., copper-base-, silicate-, and sulfide-reference materials. Consequently, it is possible to determinate major and minor element concentrations in copper alloys, i.e., Cu, Sn and Zn, using silicate and sulfide reference materials as external calibrators, without any matrix effect and over a wide range of concentrations (from wt.% to ppm). Equally, Cu, Sn and Zn concentrations can be precisely determined in sulfides using homogeneous alloys (reference) materials as an external calibrator. Thus, it is possible to determine Cu, Sn and Zn in copper-base materials and their ore minerals, mostly sulfides, in a single analytical session, without requiring specific external calibrators for each matrix type. In contrast, immiscible elements in copper matrix, such as Pb and Fe show notable differences in their relative sensitivity values and ratios for different matrix-materials analyzed, implying that matrix-matched external calibrations remain to be applied for their trace quantification.

增强体表面改性在高导热金属基复合材料中的应用

随着电子技术的高速发展和电子器件的更新换代,电子封装材料的性能需求越来越高。金属基复合材料,尤其是铝基和铜基复合材料具有高导热、低膨胀、高稳定性等特点,是具有广阔应用前景的电子封装材料。然而,金刚石、石墨烯、硅等增强体与基体的润湿性差,或者在高温下与基体发生有害的界面反应,限制了此类高导热金属基复合材料的开发和应用。本文简述了金属基复合材料的界面研究进展,结合影响金属基复合材料界面结合的因素,提出了几种改善界面结合的方法。增强体表面改性是改善金属基复合材料界面的重要途径之一,常用工艺有磁控溅射法、化学气相沉积法、溶胶凝胶法、化学镀法等;最后,对增强体表面改性在高热导金属基复合材料中的应用进行分析和展望。

石墨烯和碳纳米管增强铜基复合材料的研究进展

本文回顾了碳纳米管(CNT)和石墨烯(Gr)增强铜基复合材料的研究进展,探讨了这些复合材料的制备方法、性能提升机制及潜在应用前景。CNT和Gr因独特的物理化学特性,作为铜基复合材料的理想增强相,显著提升了材料的力学性能、导电性和热导率。首先回顾了铜基复合材料的传统制备技术,包括粉末冶金法和机械合金化法,随后介绍了新兴的化学气相沉积(CVD)和电沉积法,这些技术通过直接生长或电化学沉积实现更好的界面结合。对比分析了不同方法的优缺点,指出粉末冶金和机械合金化的成本较低但可能引起增强相分布不均,而CVD法虽能制备高质量材料但成本较高且环境影响敏感。进一步分析了CNT和Gr在铜基体中的分散性及界面结合对性能的影响,强调了良好分散性和强界面结合的重要性。在力学性能方面,CNT和Gr的分散性和界面结合对复合材料的强化机制起着关键作用,包括载荷转移、晶粒细化和Orowan强化等。此外,讨论了CNT和Gr增强铜基复合材料在耐腐蚀性、磨损性能及热管理等方面的应用潜力。尽管存在挑战,但这些复合材料在电力传输、电子器件和航空航天等领域显示出巨大应用前景。未来的研究将集中于微观结构控制、制备工艺创新和多功能复合材料开发,以实现更高性能的工业应用。

镀铜石墨对铜基制动闸片组织及性能的影响

采用化学镀的方式在鳞片状石墨表面镀铜来改善铜基制动闸片中石墨和铜基体的界面结合,制定了化学镀铜配方及工艺,并研究了4种不同镀液温度对镀铜效果的影响。对镀铜后的石墨进行显微组织观察和能谱分析可知:随镀液温度的升高,镀铜效果先升后降,最好的施镀温度为50℃。用热压烧结法制备出镀铜石墨/铜基制动闸片(FM1)与非镀铜石墨/铜基制动闸片(FM0),并对其进行力学性能、物理性能测试以及制动测试,并采用扫描电镜和能谱仪对制动闸片在制动前后的表面形貌进行观察及分析。结果表明:与FM0相比,FM1中石墨分布更细小均匀,因此样品的致密度较高,硬度、抗压强度和热导率也随之增大。在不同制动初速度下,随制动初速度的提高,两种闸片的摩擦系数均出现先略微增高、后平稳,然后显著降低的趋势,但FM1的摩擦系数总体比FM0的摩擦系数更高且稳定,线磨损率也相对较小。在350 km/h高速制动条件下,由于摩擦热引起的材料表面软化,两种制动闸片的摩擦系数差别不大,都呈现显著下降趋势。

粉末冶金制备碳纳米管增强铜基复合材料研究进展

碳纳米管具有优异的力学性能和导电、导热性能,作为增强体引入铜基体中有望开发出新一代高强、结构功能一体化的复合材料。然而,碳纳米管在铜基体中的分散性较差及其与铜的润湿性问题,成为制备碳纳米管增强铜基(CNTs/Cu)复合材料的主要挑战,并显著影响了复合材料的性能。本文对目前有关制备碳纳米管增强铜基复合材料的主要方法包括碳纳米管前期预处理方法、碳纳米管在铜粉末中分散的方法、复合材料的烧结方法进行总结,概述复合材料的力学性能、摩擦磨损性能以及导电导热性能的研究进展,并提出思考和展望,以便为制备CNTs/Cu复合材料研究提供参考。

壳核结构氧化铝@石墨烯复合粉末增强铜基复合材料摩擦学性能研究

如何充分发挥润滑组元和耐磨组元的协同作用以提高铜基复合材料摩擦学性能仍面临具大的挑战。以石墨烯为润滑组元,氧化铝为耐磨组元,对比了氧化铝和石墨烯组装为壳核结构前后对铜基复合材料摩擦学性能的影响。结果表明,与氧化铝和石墨烯分别以独立相分布于铜基体的情况相比,氧化铝和石墨烯组装为壳核结构后可以提高铜基复合材料的致密度、硬度,并有利于在磨痕表面形成连续且具有保护性的摩擦层。因此,在10~40 N载荷范围内干摩擦,后者比前者具有更低的摩擦因数和磨损率。

石墨烯化学镀铜对放电等离子烧结石墨烯增强铝基复合材料组织和性能的影响

通过化学镀方法得到镀铜石墨烯粉末,再通过静电自组装方法将镀铜石墨烯粉末与铝粉混合,然后经放电等离子烧结工艺制备镀铜石墨烯增强铝基复合材料,研究了不同质量分数(0.1%,0.2%,0.3%,0.4%,0.5%)镀铜石墨烯增强铝基复合材料的微观结构和性能,并与质量分数0.1%未镀铜石墨烯增强铝基复合材料进行对比。结果表明:镀铜石墨烯在复合材料中分散均匀,复合材料的相对密度均在99%以上;铝和铜发生反应生成了中间相Al_(2)Cu,但未有Al_(4)C_(3)界面相生成;镀铜石墨烯增强铝基复合材料的硬度和耐磨性能均优于未镀铜石墨烯增强铝基复合材料;随着镀铜石墨烯含量的增加,复合材料的硬度先升高后降低,磨损质量损失和摩擦因数均呈先减小后增加的趋势。当镀铜石墨烯的质量分数为0.2%时,复合材料具有优异的综合性能,其硬度为74.7 HV,磨损质量损失和摩擦因数均最小,分别为0.0023 g和0.259,磨损机制为氧化磨损。

铜基体铬合金化对二硫化钼/铜复合材料摩擦学性能的影响及作用机制研究

基于铜基体铬合金化的策略,研究了铬含量对二硫化钼/铜复合材料在氮气气氛下摩擦学性能的影响。结果表明,在复合材料中加入1.5wt%铬,摩擦系数低至0.07,磨损率为2.4×10^(-4)mm^(3)·N^(-1)·m^(-1),分别是未添加铬的复合材料的64%和20%。通过透射电镜、X射线光电子能谱、扫描电镜分别对二硫化钼/铜界面结构、摩擦层成分及磨痕亚表层形貌进行了详细的分析,揭示了铜基体铬合金化对二硫化钼/铜复合材料摩擦学性能的作用机制。

基体铬合金化增强石墨烯/铜复合材料摩擦学性能研究

如何通过优化石墨烯/铜复合材料的界面结构来提高复合材料的摩擦学性能成为石墨烯增强铜基复合材料领域重要的研究方向之一。采用铜铬合金(CuCr)作为基体材料,还原氧化石墨烯(RGO)作为增强相,通过溶液搅拌混合和热压烧结工艺制备得到了RGO/CuCr复合材料。对比了添加铬元素前后复合材料的减摩耐磨性能,基于磨痕表面成份和形貌的分析探讨了铜基体铬合金化对石墨烯/铜复合材料摩擦学性能的作用机制。结果表明,铜基体铬合金化使复合材料具有更小更稳定的摩擦因数和更低的比磨损率,特别是在高载荷工况下。性能提高的原因归结为铜基体铬合金化有利于在摩擦过程中复合材料表面形成致密而连续的富石墨烯摩擦层。

高导电高耐热铜合金及铜基复合材料的研究现状与展望

高导耐热铜基材料作为现代高新技术用关键材料之一,已被广泛应用于轨道交通、电子通信和航空航天等领域。本文从铜合金和铜基复合材料两大领域入手,介绍了常见高导耐热铜材料的设计思路、制备方法、微观组织结构、力学性能和物理性能,并对其导电机制和高温强化机理进行了归纳和阐释,最后对高导耐热铜基材料的研究现状和未来发展进行了总结与展望。

多步法原位制备TiB2颗粒增强点焊电极用铜基复合材料及其应用

为提高点焊电极的使用寿命,采用多步法制备TiB2增强的铜基复合材料。采用X射线衍射(XRD)、金相显微技术、扫描电镜(SEM)等表征手段对多步法制备的TiB2增强的铜基复合材料物相、微观形貌进行分析。通过对复合材料力学性能指标测量发现,多步法制备所制备的铜基复合材料具有较好的综合力学性能,将多步法制备的铜基复合材料加工成点焊电极,其寿命测试结果相较于其它对比样最高,寿命达到1500个焊点,是普通铬锆铜点焊电极寿命的2.6倍。