Copper-based Metal Matrix Research Articles

Electrochemical Study of Spark Plasma-Sintered Copper Reinforced with Ni/SiC Micron-Sized Particles for Electrical Applications

In the research study, incorporation of Cu with hard SiC and Ni micron-sized particles was applied in the fabrication of a multifunctional copper-based metal matrix composite using spark plasma sintering. The developed spark plasma-sintered Cu–xNi and Cu–xNi–xSiC composite charateristics were studied by conducting morphological analysis, electrochemical, microhardness, and densification tests. Analytical equipments used include scanning electron microscopy, equipped elemental dispersive spectroscopy, X-ray diffractometry, and Vickers hardness tester. Electrochemical characterizations using potentiodynamic polarization for the electrochemical stability of the sintered composite in 0.5 M H2SO4 was also carried out. 96% densification and 90.20% corrosion resistance were obtained. The Cu–Ni composite showed an increase in corrosion resistance as a result of Ni addition in H2SO4 environment, while Cu–xNi–xSiC composite showed a slight decrease in corrosion resistance with excess SiC. It can be inferred that Cu–xNi and Cu–NixSiC composites improves the hardness values and corrosion resistance for electrical application when applied.

Wear behavior of copper matrix composites reinforced by γ-Cu5Zn8 nanoparticles

This paper investigates sliding wear behavior of copper matrix composites, reinforced by γ-Cu5Zn8 intermetallic nanoparticles. In this research, first, γ-Cu5Zn8 single phase intermetallic ingot was prepared; then, through mechanical milling method, copper based metal matrix composites with different amounts of high-strength γ-Cu5Zn8 nano-particle were produced. Next, X-ray diffraction (XRD) test was carried out to analyze the progress of mechanical alloying. The investigated samples were formed by cold pressing at 800MPa, followed by spark plasma sintering (SPS), and the samples were subjected to microstructural and mechanical characterization. Finally, the wear test with an experimental plan of load of 10N and sliding speed of 0.5m/s was conducted on Pin-On-Disk machine for a total sliding distance of 1000m. The nanocomposites wear rate and the coefficient of friction decreased with the increase of reinforcement contents. The worn surfaces were analyzed via scanning electron microscopy (SEM), it was revealed that abrasive wear and delamination were the dominant mechanisms during the wear test.

Experimental Investigation of True Stress and True Strain on Copper Based Metal Matrix Composite during Compression Test using Design of Experiments

Objective: In this Paper, the effect of reinforcement content, load and time was analysed on the true stress and true strain during compression testing of (Copper/Silicon Carbide) Cu/SiC composite using design of experiment. Methods:Statistical analysis is performed to identify the significant factor which affects the mechanical behaviour of the composite.Three types of composite samples were made-up using different SiC content by stir casting process. The true stress and true strain of composites were evaluated for a defined variety of load and time. Findings: With the increase of SiC content, load, and time the true stress of a composite improved. With the increase of SiC content, true strain decreased while with increase of load and time, true strain increased. Vickers hardness test is also performed on developed samples. It is found that percentage increase in the reinforcement content of MMC increases the hardness of the composite. Applications/Improvements: More analysis and evaluation on copper composite can be performed by varying various parameters like increasing reinforcement percentage and tests can be conducted at elevated temperatures.

Copper Metal Matrix Composites Reinforced by Titanium Nitride Particles

Copper based Metal Matrix Composites are promising materials for electrical and electrotechnical applications such as electronic packaging and contacts, resistance welding electrodes, heat exchangers etc. Introducing the ceramics particles into the copper matrix allows to achieve a higher mechanical properties comparing to pure copper. The literature shows the variety of reinforcement materials are used. The most commonly strengthening phase include: oxides Al2O3,Y2O3, SiO2, carbides SiC, WC, TiC, ZrC, borides TiB2, ZrB2 and others such us volcanic tuff, carbon or intermetalic phases Al-Fe. [1-7]. It is obvious that reinforcement material without TiN leads to decrease the electrical conductivity of copper. Preliminary investigations concerning nanoscale Cu-based composites with TiN particles were presented in papers [10, 11]. Powder metallurgy (PM) process leads to obtain uniform distribution of strengthening phase in matrix. In order to achieve uniform distribution the process parameters such as mixing and selection the sizes of particles must be appropriate selected. The another factor of decreasing the mechanical and electrical properties by using PM route is porosity. Conventional PM process includes pressing and sintering does not always allow to achieve the high density what is one of the main criterion for high electrical conductivity material. The hard ceramic particles in metal matrix which are not deformable make difficult the densification process. In some cases the use of more advanced methods of production is desirable. The use of titanium nitride particles is justified by their high electrical conductivity in compare to the other reinforcement materials.

Mathematical Modeling of Machining Parameters in Electrical Discharge Machining with Cu-B<sub>4</sub>C Composite Electrode

Copper based metal matrix composite reinforced with Boron Carbide is a newly developed Electrical Discharge Machining (EDM) electrode showing better performance than the conventional copper based electrode. Right selection of machining parameters such as current, pulse on time and pulse off time is one of the most important aspects in EDM. In this paper an attempt has been made to develop mathematical models for relating the Material Removal Rate (MRR), Tool Removal Rate (TRR) and Surface roughness (Ra) to machining parameters (current, pulse-on time and pulse-off time). Furthermore, a study was carried out to analyze the effects of machining parameters on various performance parameters such as, MRR, TRR and Ra. The results of Analysis of Variance (ANOVA) indicate that the proposed mathematical models, can adequately describe the performance within the limits of the factors being studied. Response surface modeling is used to develop surface and contour graphs to analyze the effects of EDM input parameters on outer parameters.

Performance analysis of Cu-B<SUB align="right">4C metal matrix composite as an EDM electrode

Performance of electrode materials is one of the important factors that determine the quality of the machined component and the cost involved in the operation of electro discharge machining (EDM) process. Low electrode wear resistance in graphite and copper electrodes necessitated the development of sintered composite electrodes for EDM operation. In this paper, authors attempted to develop a new copper-based metal matrix composite (Cu-B4C) to get an optimum combination of wear resistance, electrical and thermal conductivity. Here the copper-boron carbide composite was developed through powder metallurgy route and EDM experiments were carried out using mild steel specimen. Copper composite with 40% boron carbide reinforcement exhibits better metal removal rate (MRR) and tool removal rate (TRR) compared to conventional copper electrode. SEM and XRD results show the surface modification and formation of boron, B4C reinforced layer on the surface of mild steel work piece when machined with composite electrode.

Dry Sliding Wear of a Powder Metallurgy Copper-based Metal Matrix Composite Reinforced with Iron Aluminide Intermetallic Particles

In the present study, dry sliding wear behavior of a powder metallurgy copper alloy matrix composite containing iron aluminide (Fe3Al) intermetallic particles was investigated using a pin-on-disk machine. A sintered copper alloy (Cu—90%, Sn—10%) was used as matrix. Reinforcement Fe3Al particles were prepared by mechanical alloying (42 h) and used as reinforcement (10 and 20 vol%) in the matrix. The processing of the composites included mixing and cold compaction followed by sintering at 850 °C. The influence of Fe3Al additions on the dry sliding wear behavior was studied at loads of 20 and 40 N at sliding distances of 2160, 3240, 4320, and 6480 m. The study showed that the composite exhibited lower wear rate than that of the matrix and the wear rate was influenced by the volume percentage of Fe3Al particles. It is understood that iron aluminide particle reinforcement has a beneficial effect on the wear properties by providing better support to the matrix. The wear mechanisms could be interpreted with scanning electron microscopy (SEM) examination of the worn surfaces.

The influence of mechanical adhesion of copper coatings on carbon surfaces on the interfacial thermal contact resistance

The weak mechanical and thermal interface in Copper based Metal Matrix Composites (MMCs) reinforced by carbon fibers is the background of this research study. In order to investigate the mechanical adhesion strength and the thermal contact resistance between copper and carbon, a simplified model system based on coated flat carbon substrates has been used. Cu coatings of approximately 1 μm thickness on intermediate Ti bond layers have been deposited on carbon substrates by a sputter deposition process. The resulting different adhesion strengths between coating and substrate have been measured by means of a pull-off method, and non-destructive photothermal method, giving information on the depth-resolved thermal properties of the samples has been used to determine the Thermal Contact Resistance (TCR). By combining the results of mechanical adhesion tests and of photothermal IR radiometry, the correlation of the mechanical adhesion of Cu coatings on Carbon surfaces with the interfacial thermal contact resistance has been analysed.

Development of copper-based metal matrix composites for electric motor commutator rings : S.A. El-Badry et al. (AlAzhur University, Cairo, Egypt)

Development of copper-based metal matrix composites for electric motor commutator rings : S.A. El-Badry et al. (AlAzhur University, Cairo, Egypt)

Cu Based Carbon Fibre Reinforced Metal Matrix Composites — Improved Fibre Distribution/ Kohlefaserverstärkte Verbundwerkstoffe mit Cu-Matrix — verbesserte Faserverteilung

Copper based metal matrix composites with carbon fibres as reinforcement were produced by squeeze casting the molten metal into a preform of carbon fibres. It is shown, that the fibre distribution of the reinforcement in the MMC is determined by the processing route of the preform. Preparation of the preforms by dispersing the fibres in water results in clustering and channeling. By separating and using the fibres in the dry condition a uniform fibre distribution is achieved.

Carbon diffusion in copper-based metal matrix composites

The heights of diffusion barriers for copper-based composite materials with carbon whiskers or fibers are calculated. It is shown that the alloying of the matrix by an additional element, substituting copper in an interstitial Cu-C solid solution changes the value of the barrier and the migration entropy. These substitutional impurities significantly influence the diffusivity of carbon in the copper matrix. Zirconium is predicted as the best alloying element for preventing the diffusion of carbon in Cu-C alloy.

Carbon diffusion in copper-based metal matrix composites

Carbon diffusion in copper-based metal matrix composites