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Open access

T. Knych, M. Piwowarska-Uliasz and P. Uliasz

Abstract

The main scientific challenge of the study was the selection of the zirconium amount, which will allow achieving high electric and strength properties of the alloy. The analysis of chemical compositions of the thermal resistive, conducting AlZr alloys allowed to estimate the most advantageous amount of zirconium, which was found to be within the range: from 0.05 to 0.32 wt % of Zr. The main aim of the study was the investigation of electric properties of alloys of the selected chemical compositions, being within the above given range. The endeavours were focused on determining the heat treatment influence (artificial ageing) on the resistivity of the AlZr alloys in the cast form. On these bases the ranges of obtainable electrical properties were estimated for the investigated alloys, which enabled the selection of optimal conditions of the heat treatment.

Open access

T. Knych, M. Piwowarska and P. Uliasz

Studies on the Process of Heat Treatment of Conductive AlZr Alloys Obtained in Various Productive Processes

A novelty in electroenergetics of the recent years are anti-blackout conductors of the HTLS type. These conductors allow for an above average increase of the transmission capacity of electric energy through overhead lines. The high temperature work of such conductor is possible with the use of thermally resistant aluminium alloys with the addition of zirconium. Compared to the traditionally applied material of the EN AW 1370 class, those alloys' permissible work temperature is at the level of 150 to 230°C (aluminium 80°C). The production technology for the alloys of this type includes a line of continuous casting and rolling of the wire rod, and next, its long-term heat treatment. The aim of the process of the heating of the wire rod is obtaining the desired level of the material's properties, which will make it possible to obtain the final properties of the wires assigned for the creation of conductors. The paper presents the results of the studies aiming at the description of the influence of the heat treatment of the material obtained in various production process conditions on its mechanical and electric properties.

Open access

H. Paul, P. Uliasz, M. Miszczyk, W. Skuza and T. Knych

The crystal lattice rotations induced by shear bands formation have been examined in order to investigate the influence of grain boundaries on slip propagation and the resulting texture evolution. The issue was analysed on Al-0.23wt.%Zr alloy as a representative of face centered cubic metals with medium-to-high stacking fault energy. After solidification, the microstructure of the alloy was composed of flat, twin-oriented, large grains. The samples were cut-off from the as-cast ingot in such a way that the twinning planes were situated almost parallel to the compression plane. The samples were then deformed at 77K in channel-die up to strains of 0.69. To correlate the substructure with the slip patterns, the deformed specimens were examined by SEM equipped with a field emission gun and electron backscattered diffraction facilities.

Microtexture measurements showed that strictly defined crystal lattice re-orientations occurred in the sample volumes situated within the area of the broad macroscopic shear bands (MSB), although the grains initially had quite different crystallographic orientations. Independently of the grain orientation, their crystal lattice rotated in such a way that one of the f111g slip planes became nearly parallel to the plane of maximum shear. This facilitates the slip propagation across the grain boundaries along the shear direction without any visible variation in the slip plane. A natural consequence of this rotation is the formation of specific MSB microtextures which facilitates slip propagation across grain boundaries.

Open access

T. Knych, M. Piwowarska-Uliasz, P. Uliasz and J. Wiecheć

Abstract

The subject of the present article consists in obtaining the wire production material with the controlled, during the heat treatment, level of electrical and mechanical properties. In the case of the AlZr alloys the appropriate strength properties are obtained in the technological process through the introduction of the specified value of the cold working (work-hardening). In turn,the AlZr alloy resistivity value is dependent on both the amount of the zircon additive and its placement characteristics in the aluminium structure (solid solution or emissions). The paper presents comparative resistivity and hardness tests of the AlZr alloy material with the zircon content ranging from 0.05 to 0.32% mas. Zr produced in the continuous casting technology as well as in the continuous casting and rolling technology.

Open access

M. Jabłoński, T. Knych, A. Mamala, B. Smyrak and K. Wojtaszek

Abstract

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.

Open access

T. Knych, G. Kiesiewicz, P. Kwasniewski, A. Mamala, B. Smyrak and A. Kawecki

Abstract

This paper presents the research results of copper Covetic metallurgical synthesis along with the characterization of cast material and the processing of casts into wires. The Cu-C composite production method was based on patent applications of Third Millennium Metals. Obtained materials were tested for their chemical composition (including Secondary Ion Mass Spectrometry (SIMS) analysis for carbon presence), mechanical properties and electrical conductivity. Measurements were also performed for wires which were first cut from obtained casts and next cold drawn into final wire form. Produced wires were tested for their mechanical and electrical properties. Electrical conductivity of wires was measured with the use of high precision Thompson’s- Kelvin’s bridge type device. A key objective of the research was to determine if Covetic copper has higher electrical conductivity than pure oxygen free copper.

Open access

A. Kawecki, T. Knych, E. Sieja-Smaga, A. Mamala, P. Kwaśniewski, G. Kiesiewicz, B. Smyrak and A. Pacewicz

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.

Open access

P. Kwaśniewski, G. Kiesiewicz, T. Knych, A. Mamala, M. Gniełczyk, A. Kawecki, B. Smyrak, W. Ściężor and E. Smaga-Sieja

Abstract

Currently we can observe a worldwide trend to find new materials with extraordinary properties. In particular these researches are aimed to find a method to improve electrical conductivity, mechanical properties, corrosion resistance and rheological behavior of known materials. This effect can be achieved by a synthesis of modern carbon materials with metals. In this paper authors presented research results of synthesis process for Cu-graphene and Cu-CNT’s composites obtained by the mechanical synthesis in cold drawing process. The article presents also the results of electrical conductivity measurements and structural analysis of carbon particles presence in copper matrix. The research has shown that obtained composites have electrical conductivity lower than used copper base material. Additionally, the structural analysis has shown that after the drawing process carbon materials particles are mechanically pressed into Cu in the matrix, and these particles do not participate in the current flow, creating an actual barrier for electrons transport.

Open access

A. Mamala, T. Knych, P. Kwaśniewski, A. Kawecki, G. Kiesiewicz, E. Sieja-Smaga, W. Ściężor, M. Gniełczyk and R. Kowal

Abstract

The paper shows a new idea of aluminium alloys. New alloys with specially selected alloying element i.e. silver have electrical conductivity similar to pure aluminium at ambient temperature and better than pure aluminium electrical conductivity at increased temperatures. Al-Ag alloys for electrical applications (mainly for electrical conductors) due to high electrical conductivity at increased temperatures at the level of the maximum conductor working temperatures give possibility of better current capacity of conductors.

The experimental results of basic mechanical properties and the electric conductivity versus temperature relation are shown in the paper as well as examples of the tested material operational properties.

The summary gives theoretical analysis based on examples of the potential applications of Al-Ag alloys (new conductor designs) which provide the benefits of the new solutions in comparison to traditional conductors.