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Przewodowe stopy na bazie aluminium

Knych T., Mamala A., Smyrak B.

Rudy i Metale Nieżelazne

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2004

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R. 49, nr 6

292-295

PL

Przedstawiono stopy na bazie aluminium przeznaczone na przewody elektroenergetyczne. Materiały te zestawiono w dwóch grupach: stopy klasyczne z grup AlMgSi, AlCuMg, AlMg, AlFe oraz nowoczesne odporne cieplnie stopy z grupy AlZr.

EN

The history of overhead electrical power engineering stared in 1882 in Germany, where the first DC line was built. Traditionally, considering material properties, the basic material for conductors was, and still is, copper. The first conductors were made of this metal. At the beginning of the 20th century copper became a strategic material and therefore, aluminium started to be used in electrical power systems. Aluminium, although known since 1825, was not attractive for 19th century electrical power engineering because of its high price. With the development of modern methods for its winning it has become competitive with other commonly used metallic elements. However, despite its more advantageous conductivity-to-density ratio compared to that of copper (which is important index in overhead line conductors), aluminium conductors for overhead lines had to be steel-reinforced due to their low mechanical properties. In the first solutions in this field, the whole mechanical load was carried by a steel core, whereas aluminium layer was conducting electricity. This resulted in high effort of the core material and great sags of such conductors. Therefore, more economic approach aimed to reduce height of the supporting constructions was implemented, leading to the development of steel-aluminium conductors, which are now well known and commonly used. This solution is based on application of cold-drawn aluminium which, besides conducting electric current, takes over a part of mechanical load, whereas high strength steel wires making up a core take over the remaining portion of a tension. However, bimetallic conductors create a number of exploitation problems resulting from different physical properties of the constituent materials, high mass of a conductor, presence of ferromagnetic material, corrosion risk, and others. These problems have become an inspiration for the development of homogeneous conductors. Such conductors are sometimes made of aluminium, copper and steel, but because of many shortages such as insufficient mechanical strength (aluminium), high mass and price (copper), and high losses (steel), their mass application appeared to be impossible. The only economically and technically justified solution are aluminium alloys based homogeneous conductors, so called alloyed conductors. The first electricity line of that kind was built in France in 1928. The world-wide interest in this group of conductors dates back to the middle of the 20th century, when the dynamic industrial development resulted in considerable demand for energy, and technologies for fabrication and processing of the aluminium alloys for conductors were sufficiently mastered. The current trends in the field of overhead electric power systems in reference to the materials for the conductors include: improvement of aluminium alloys designed for conductors, development of composite cores aimed to replace steel in bimetallic conductors, and general improvement of the mechanical, electric and operating properties of the conductors.

2

Prognozowanie parametrów siłowych wyciskania na gorąco aluminium i jego stopów

Zasadziński J., Richert J., Libura W.

Rudy i Metale Nieżelazne

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2004

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R. 49, nr 3

131-134

PL

Przedstawiono rozważania dotyczące parametrów siłowych wyciskania na gorąco na przykładzie wyciskania przciwbieżnego kształtowników o przekroju kołowym z aluminium w gat. 1050 oraz stopów 6063 i 2017. Analizą objęto dotychczas stosowany zakres temperatur wyciskania (0,7-0,83 temperatura homologiczna) oraz zakres wysokich temperatur od 0,8 do 0,95. Na podstawie przeprowadzonych obliczeń wykazano, że średnie naprężenie wyciskania stopu 2017 jest 15 razy wyższe od naprężenia wyciskania, które wystąpi w przypadku wyciskania tego stopu w temperaturze homologicznej około 0,93.

EN

Discussion on the force parameters in hot extrusion has been presented, taking indirect extrusion of profiles from 1050 grade aluminium and 6063 and 2017 alloys with a circular cross-setion as an example. The analysis covered currently used range of extrusion temperatures (0,7-0,83 of the homologous temperature) and a high-temperature range of 0,8-0,95 HT. Based on the calculations it has been shown that an average extrusion stress in the case of 2017 alloy is 15 times higher than that necessary in extruding this alloy at the homologous temperature of about 0,93.

3

Synteza kompozytów "in situ" Al-TiC oraz Cu-TiC z wykorzystaniem gazu reaktywnego

Fraś E., Janas A., Kolbus A., Górny M.

Inżynieria Materiałowa

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2000

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R. XXI, nr 2

48-55

PL

W pracy opisano metodę syntezy TiC w aluminium i miedzi, która wykorzystuje przedmuchiwanie metali za pomocą metanu jako gazu reaktywnego w celu otrzymywania kompozytów in situ. Przedstawiono teoretyczne podstawy syntezy i kinetyki tworzenia się węglików tytanu w ciekłych stopach aluminium-tytan oraz miedź-tytan z uwzględnieniem reakcji na powierzchni rozdziału ciało stałe-ciecz, obejmujące zarodkowanie i wzrost cząstek TiC. Badania strukturalne przeprowadzono z wykorzystaniem mikroskopu optycznego oraz dyfrakcji rentgenowskiej. Wykazano, że w skład struktury otrzymanych kompozytów wchodzą węgliki tytanu rozmieszczone w przestrzeniach międzydendrycznych o przeważających wymiarach od 1 do 4 mikrometra w przypadku stopów z miedzią oraz około 2 mikrometry w przypadku stopów z aluminium. Badania wykazały także obecność Al4C3, Al3Ti oraz CuTi odpowiednio w stopach na bazie aluminium i miedzi. Stwierdzono, że udział objętościowy wzmacniających cząstek TiC w kompozytach zależy od zawartości tytanu oraz czasu syntezy węglika. Przedstawiony proces syntezy węglika tytanu w osnowie aluminium i miedzi może posłużyć jako ekonomicznie uzasadniona metoda otrzymywania kompozytów typu MMC.

EN

The present work undertaken to a novel "in situ" process in which reactive gas (methane) injection were used to synthesis of fine TiC particles in aluminium and copper matrix. A comprehensive kinetic mechanism of "in situ" TiC synthesis, which includes a solid-liquid interface reaction between the carbon particles and Al-Ti, Cu-Ti melts and multiple nucleation and growth of TiC from melt was proposed. Microstructures of the experimental materials were comprehensively characterized by optical microscopy and X-ray diffraction. The tipical ingot metallurgy microstructures exhibit aggregates of TiC particles segregated generally at alpha-Al and alpha-Cu dendritic boundaries and consisting of fine particles of 1 to 4 and 2 micrometers in size, respectively for copper and aluminium alloys. Microstructural analysis demonstrated also the presence of Al4C3 and Al3Ti in Al-based composites and Cu3Ti in Cu-based composites. It has been shown that the volume fraction of reinforcement is limited by the time of synthesis and content of Ti in melt. The synthesis process of TiC in aluminium and copper matrix is envisioned as commercially viable technique for continuous processing of cost effective metal matrix composites.