Electrical dislocation resistivity and anisotropic scattering in high‐purity copper single crystals

Abstract

The experimental dislocation rcsistivity (or the deviation from Matthiessen's rule (DMR)) at 4.2 and 77 K of sevcral single slip and multislip crystals was investigated. Additionally low-field Hall effect nieasurernents at 4.2 K using a dc SQUID picovoltmeter were pcrformed in order to study the anisotropy of electron-dislocation and electron-impurity scattering directly. It is shown that, oxygen annealing applied to increase tiic "elcctrical purity" of the crystals does not change the character of the scattering behaviour. The anisotropy parameters Adis for electron-dislocation scattering derived within the two-group model are in good agreement with recent rcsults for high-purity polycrystals.

The Deviation from Matthiessen's Rule and Electrical Dislocation Density Measurement in Dilute Cu-Au Alloys

“…The electrical dislocation density measurement relies on the value of the specific dislocation resistivity R d and the modelling of the DMR contributions d ipd and d ip occuring in (4). If the mean free path of the conduction electrons (at 4.2 K) is larger than the typical fluctuation in dislocation density due to ªcellsº (size 0.5 to 1 mm) and ªcell wallsº (size one tenth of the cell size), the electrical resistivity does a proper averaging of the dislocation density.…”

Elastic and plastic strain effects on eddy current response of aluminium alloys

“…That is, knowing the elastic coefficients of electrical conductivity of the material under examination, it is possible to infer the residual stress levels from a measurement of electrical conductivity of the material. Cold work evaluation is possible owing to the decrease in electrical conductivity due to dislocations concentration [13,14]. However, in practice, the change in apparent EC conductivity is due in part to elastic strains (residual stress), and in part to plastic strains (cold work) [15], which complicates the interpretation of EC results.…”