Electrical Properties Of Wires Research Articles

Rheological Resistance of CuAg15 Alloy Wires

The paper presents the results of studies on obtaining the alloy and generating a set of very high mechanical and electrical properties of wires. The paper also presents the results of testing the rheological resistance in the form of stress relaxation tests carried out on the wires after various thermomechanical treatment processes. The optimum parameters of the thermo-mechanical treatment of the alloy were determined, enabling obtaining the most favorable mechanical and electrical properties of wires. The relationships of the influence of the material and its deformation on the changes in the mechanical and electrical properties of wires were determined. In addition, a microstructural analysis was carried out of casts and wires using scanning electron microscopy. Cast material was subject to observation and the material at successive stages of heat treatment.

Effect of Iron Addition to Aluminium on the Structure and Properties of Wires Used for Electrical Purposes

Eight hypoeutectic aluminium alloys with iron content within the range of 0.07-1.09% by weight, were examined. The structure, the mechanical and electrical properties of wires used for electrical purposes were studied. The batch material for the drawing process was wire rod obtained from the continuous casting and rolling line by Continuus-Properzi method. It has shown a linear relationship between mechanical properties of wire rod, a higher plasticity of wire after drawing process and an increase in thermal resistance of the material with increasing iron content. The findings enable to draw conclusions of basic and application characteristics, pointing to the possibility of using aluminium with higher iron content in the wire drawing process of small diameter and microwires for the production of automotive bundles, accumulator cables and winding wires.

Comparison of microstructure and strength in wire-drawn and rolled Cu-9 Fe-1.2 Ag filamentary microcomposite

Comparison of microstructure and strength of Cu-9 Fe-1.2 Ag microcomposite wires and sheets obtained by cold drawing or cold rolling combined with intermediate heat treatments has been made. The primary and secondary dendrite arms are aligned along the drawing or rolling direction and elongated into filaments after cold working. The microstructural scale of wire-drawn microcomposites was found to be finer than that of rolled microcomposites at the same drawing strain. The more effective microstructural refinement induced by unidirectional metallic flow and co-deformation of filament and Cu matrix resulted in finer microstructure in microcomposite wires. The ultimate tensile strength and the conductivity of wire-drawin Cu-Fe-Ag microcomposite were higher than those of rolled Cu-Fe-Ag microcomposites. The strength of Cu-Fe-Ag microcomposites is dependent on the spacing of the Fe filaments in accord with a Hall-Petch relationship. The good mechanical and electrical properties of wires may be associated with the more uniform distribution of fine filaments. The fracture surfaces of Cu-Fe-Ag wires and sheets showed ductile-type fracture and iron filaments were occasionally observed on the fracture surfaces. The fracture surface of Cu-Fe-Ag wires showed generally finer microstructural morphology than that of Cu-Fe-Ag sheets, consistent with the finer microstructural scale in Cu-Fe-Ag wires.

Length-Dependent Resistance of Thin Wires

The electrical properties of wires with cross-sectional areas of order 1 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}11}$ ${\mathrm{cm}}^{2}$ and lengths as small as 0.2 \ensuremath{\mu}m have been studied. At temperatures below about 10 K, the resistance of the wires increases with decreasing temperature, as found in previous studies of much longer wires. For wires shorter than about 5 \ensuremath{\mu}m, the resistance rise decreases as the length of the wire is decreased. From these results a characteristic length scale of approximately 0.2 \ensuremath{\mu}m at 1.5 K is found, in good agreement with the current theory.

Experimental study of localization in thin wires

The electrical properties of wires with cross-sectional areas in the range 1 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}11}$ to 3 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}10}$ ${\mathrm{cm}}^{2}$ have been studied. At temperatures below about 10 K, the resistance of the wires increases as the temperature is lowered. The magnitude of the resistance rise increases both as the cross-sectional area of the wire is made smaller and as the amount of randomness is increased. This behavior is in qualitative agreement with the recent predictions by Thouless concerning localization in thin wires. However, the magnitude of the resistance rise is much smaller than originally predicted, and to obtain quantitative agreement with the experimental results it is necessary to assume that the rate at which electrons are inelastically scattered is proportional to the temperature and independent of the size of the wire. This is not consistent with the usual electron-phonon or electron-electron scattering process, and suggests that either the sample geometry affects these processes or that scattering from some other source, such as the tunneling levels believed to be present in all highly disordered systems, is the dominant inelastic scattering process. Experiments on thin films with resistances per square in the range 15 to 100 $\ensuremath{\Omega}$ are also reported. The behavior of the films is similar to that of the wires; they exhibit a resistance rise at low temperatures, and the magnitude of the rise becomes larger as the resistance per square is increased. These results are in good agreement with the predictions of Abrahams et al. for localization in two dimensions and correlate well with recent experimental results of Dolan and Osheroff. The effect of a magnetic field has also been investigated. It is found that a field of 75 kOe has no significant effect on the behavior of the wires. However, a field of this size appears to change the behavior of the films markedly. While our results are all consistent with theoretical predictions based on localization, they are also consistent with recent theories based on electron-electron interaction effects in disordered systems.

Experimental Study of Anderson Localization in Thin Wires

The electrical properties of wires with cross-sectional areas ($A$) in the range 1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}11}$ to 3\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ ${\mathrm{cm}}^{2}$ have been studied. At temperatures below about 10 K the resistance of the wires increases with decreasing temperature. The size of the increase varies as ${A}^{\ensuremath{-}1}$ and becomes larger as the impurity resistance is made larger, in qualitative agreement with recent theoretical predictions by Thouless. The size of the increase is in order-of-magnitude agreement with the theory but the temperature dependence is not.