Reinforced Copper Composite Materials
Copper Composite Materials Reinforced with Powdery Particles
Tech Area / Field
3 Approved without Funding
VNIIKhT (Chemical Technology), Russia, Moscow
- MISIS (Steel and Alloys), Russia, Moscow
- University of Ottawa, Canada, ON, Ottawa\nUniversiteit Antwerpen, Belgium, Antwerpen\nUniversity of Missouri, USA, MO, St Louis\nINASMET, Spain, San Sebastian
Project summaryProblem of improving performance attributes (properties) of copper materials is actual task, because copper is the wide distributed metal in engineering.
Electronics requires materials that possess a high thermal conductivity and electrical conductivity in combination with a low coefficient of linear expansion.
Metal matrix composites based on copper and different reinforcements have lately become an object of studies for applications in electronics frames (electronics compaction), as they can provide for a lower linear expansion coefficient as compared with the most widespread type of MMC based on aluminum alloys.
Herewith, materials with a small size of reinforcing particles are required, as in this case the tensions in the body of the composite, which occur owing to the difference of the linear expansion coefficients of the matrix material and reinforcing particles’ material, are reduced.
The use of the infiltration method widespread in production of aluminum composites becomes in this case rather problematic because of the following reasons:
- the melting temperature of copper is considerably higher than that of aluminum
- impregnation (infiltration) methods can not change the size of the reinforcing particles, i.e., a more expensive initial material for reinforcing particles is required to produce a composite with a small size of reinforcing particles (the smaller the size, the more expensive the reinforcing material is).
Therefore, the following method of producing composite materials is proposed in the project: mechanical alloying to produce granules of composite + subsequent compaction to produce solid material.
As previous studies have shown, this method makes it possible to achieve a high adhesion of reinforcing particles and matrix material. Therewith, the reinforcing particles are comminuted (in the case of use of initial big particles: up to 70% of the total volume become nanoparticles, the other particles’ size does not exceed 1 µm). The granules produced by mechanical alloying should be compacted into a solid material. This is a sufficiently complex problem, especially for materials with a high content of reinforcing particles. However, the correct choice of temperatures and deformation modes makes it possible to achieve a high quality of solid material.
The major aim of the project is development of method of producing high-quality materials with high thermal conductivity parameters, increased parameters of electrical conductivity as compared with similar composite materials, in combination with a decreased linear expansion coefficient.
Copper and aluminum possess high electrical and thermal conductivities; therefore, they can be considered as possible matrix materials. However, the linear expansion coefficient of copper is lower than that of aluminum, so copper is proposed for the studies.
Several materials possessing a low linear expansion coefficient and a sufficiently good thermal conductivity can be taken as copper matrix reinforcements.
This project includes investigation with use of following materials. Copper with technical purity (as chips or powder with particle size not more than 500 micrometers) will be used for matrix formation. For reinforcements following materials will be used:
- onion-like carbon, produced from nano-diamonds,
- silicon carbides,
- nanopowders of silica.
For obtaining composite materials, following methods will be used:
- Part of specimens will be obtained by classic scheme of mixing powders, compaction and thermal treatment. Sometimes, it is possible to use additional operation of deformation.
- Part of specimens will be obtained by scheme:
- mechanical alloying of copper with reinforcing particles in mills with formation of granules of composite materials;
- compaction of granules;
- thermal treatment.
- structure of developed materials with optical, scanning and transmission electron microscopy;
- distribution of components with Auger-spectroscopy and X-ray analysis;
- mechanical properties will be measured
- dependences of thermal conductivity, linear expansion coefficient and electrical conductivity of the material developed on the content of reinforcements.
Results of researches will be coordinated with treatment regimes. On the basis of fulfilled researches, determination of rational technological conditions for each kind of reinforcements will be carried out.
According to developed regimes, pilot specimens of composite materials will be produced.
The project will include studies to develop the regimes of mechanical alloying of copper and powders of reinforcing particles in various proportions from 5 up to 50 vol.%. Regimes of compaction of granules, produced in mechanical alloying of the mixtures, will be developed. Materials developed will be subjected to studies to determine the adhesion between the components of the composite. Of great importance are the studies of the dependence of thermal conductivity, linear expansion coefficient and electrical conductivity (electrical resistance) depending on the content of reinforcing particles.
Thus, the following problems shall be solved in the execution of the project:
- Preparation of materials and equipment, development of methods of new materials’ R&D
- Development of the method of mechanical alloying to produce granules of composite material based on copper and different reinforcements
- Development of the method of compaction of composite granules to produce a high-quality solid material
- Studies of the structure of the material developed using optical, scanning and transmission microscopies
- Studies of the dependence of electrical conductivity, thermal conductivity and linear expansion coefficient on the composition of the composite material
- Fabrication of specimens of the materials developed and their delivery to the partner (no more than three specimens).
Expected Results and Their Application
- new method of producing composite materials on the basis of copper with different reinforcing particles will be developed. Use of nanodiamonds, nanopowders of silica and silicon carbide particles as reinforcements will allow:
- varying sense of linear expansion coefficients, coefficient of thermal conductivity and coefficient of electrical conductivity;
- varying sense of coefficient of friction in wide level.
- composite material with complex composition of reinforcements will be developed
- Database of properties of developed materials will be collected.
High quality specialists will participate in the project; this is guarantee of fulfillment of the project on high scientific level.
The main user of developed materials will be electro-engineering and automotive electronics, i.e. the project is aimed to redirect of weapon specialists for developed products for civil needs
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