Currently, there is a worldwide search for new forms of materials with properties that are significantly improved in comparison to materials currently in use. One promising research direction lies in the synthesis of metals containing modern carbon materials (e.g., graphene, nanotubes). In this article, the research results of metallurgical synthesis of a mixture of copper and two different kinds of carbon (activated carbon and multiwall carbon nanotubes) are shown. Samples of copper-carbon nanocomposite were synthesized by simultaneously exposing molten copper to an electrical current while vigorously stirring and adding carbon while under an inert gas atmosphere. The article contains research results of density, hardness, electrical conductivity, structure (TEM), and carbon decomposition (SIMS method) for the obtained materials.
Continuous pressure put on researchers all over the world these days to design materials of improved properties create opportunities to study new methods of production in conjunction with entirely new and innovative materials such as alloys or composites. The authors in the current research manufactured aluminium reinforced with glass fibre (GF) using metallurgical synthesis, which is an unconventional and not sufficiently studied method of production. The composites with 1, 2 and 5 wt.% of glass fibre were produced with additional material obtained using consolidation of aluminium powder in extrusion process as reference material with 5 wt.% of glass fibre. All the materials were subjected to series of tests in order to determine their microstructure, density, electrical properties, hardness and susceptibility to plastic working in the compression test. It was found that glass fibre during metallurgical synthesis of aluminium composite partially melted and thus did not reinforce the material as well as during extrusion, which has been observed not only in the scanning electron microscope (SEM) and energy-dispersive X-ray (EDX) analysis but also in the analysis of macroscopic physical and mechanical properties. Based on the analysed samples, it may be stated that electrical conductivity of the samples obtained via metallurgical synthesis is higher than might be estimated on the basis of the rule of mixtures and glass fibre content and concerning the sample with 5 wt.% of GF is higher (32.1 MS/m) than of the reference material obtained in extrusion process (30.6 MS/m). Similar situation has been observed in terms of hardness of the tested samples where a minor increase in hardness was noticeable as the amount of glass fibre increased in the composites obtained by metallurgical synthesis. It is believed to be related to the melting of glass fibre, which reduced the volume fraction of GF containing mainly silicon oxides and their diffusion into the aluminium matrix, thus causing solid solution strengthening.
The effect of iron and silicon addition on the structure and properties of aluminium wire rod obtained in the laboratory horizontal direct chill casting process has been analysed. In addition, the impact of laboratory wire drawing process has been examined. The addition of iron and velocity of casting increase the strength of aluminium wire rod in as-cast condition while the electrical conductivity drop acceptable. Moreover, the laboratory wire drawing process causes work-hardening wires and increase drawing tension as a result of fragmentation of structure and growth of grain boundaries. It has been shown that iron is beneficial for mechanical and technological properties of aluminium.
Research results of manufacturing composite filamentary nanostructure Cu-Ag alloys with silver addition from 5 to 15% wt. are presented in the paper. Manufacturing technology of these composites and variable solubility of silver in copper and copper in silver in the range of solid solutions. Suitable quantity and processing sequences of high deformation plastic working and heat treatment allows to obtain wires constituted from Cu and Ag fibres with nanometric transverse dimensions and in consequence provide to optimum superposition of high mechanical strength, high electrical conductivity and sufficient ductility of Cu-Ag alloys.The paper presents the method of continuous casting of alloys, selected physico-chemical properties and degree of deformation. Influence of chosen heat treatment method over electrical and mechanical properties of both casts and micro wires on mechanical and electrical properties of cast materials during converting them into micro wires with tensile strength higher than 1200 MPa and electrical conductivity higher than 40 MS/m are presented too.Research results of optical and scanning microscopy structure analysis were presented for casts and wires submitted to various thermo-mechanical strengthening.Keywords: silver-copper alloys, continuous casting, drawing, micro-wires, filamentary micro-composite, nanostructure, high conductivity, high strength Praca dotyczy badań nad kształtowaniem zespołu bardzo wysokich własności wytrzymałościowych i elektrycznych drutów i mikro-drutów ze stopów CuAg5 i CuAg15. Technologia wytwarzania drutów ze stopów Cu-Ag wykorzystuje zjawisko obustronnej zmiennej rozpuszczalności składników stopów w stanie stałym. Jak wykazały przeprowadzone badania, odpowiednie połączenie przeróbki plastycznej materiałów o strukturze odlewniczej z międzyoperacyjną obróbką cieplną umożliwia uzyskanie korzystnej kompozytowej mikrostruktury silnie wydłużonych włókien Cu i Ag o nanometrycznych wymiarach poprzecznych. Optymalizacja parametrów technologicznych pozwala na uzyskanie drutów i mikro-drutów Cu-Ag o wytrzymałości na rozciąganie w zakresie 1000÷1300 MPa przy równocześnie wysokiej przewodności elektrycznej wynoszącej 70÷85% w skali IACS.W artykule pokazano metodę uzyskania stopów Cu-Ag oraz wyniki badań wybranych własności fizykochemicznych, schemat odkształcenia oraz badania wpływu wstępnej obróbki cieplnej materiałów w stanie odlanym na zmianę własności elektrycznych i mechanicznych zarówno odlewów jak i drutów po przeróbce plastycznej. Zamieszczono także wyniki obserwacji strukturalnych przy zastosowaniu mikroskopii optycznej i skaningowej odlewów oraz ewolucję struktury po przeróbce plastycznej oraz po różnych etapach międzyoperacyjnej obróbki cieplnej.
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