The partial-wave method is used for the calculation of the residual electrical resistivity caused by dislocations and grain boundaries in various metals. The dislocation core is regarded as a resonance scattering line defect containing surplus free volume. Scattering by elastic distortions of the lattice is neglected. An estimation of the effective carrier concentration in transition metals is performed on the basis of Mott's theory. The proposed model for the evolution of the grain-boundary structure with misorientation angle regards the approach and confluence of the line defects forming the boundary, and results in a decrease of the resonance part of the total scattering cross section. The high-angle grain boundaries are assumed to consist of cylindrical voids. Taking into account the values of the steady Burgers' vectors, quite satisfactory agreement with the available experimental data is obtained.
Using the partial-wave method, the residual electrical resistivity and the additional and characteristic thermopowers of dislocations for noble and alkaline metals are calculated. Just the scattering of electrons by the dislocation core is considered. The existence of resonance electron states near the Fermi energy within the thermal scatter kBT is supposed. The lattice dilatation ΔV = bB2 (bB is the steady Burgers vector) is taken into account. Various forms of rectangular potential simulating the dislocation core are investigated. It is shown that unlike the dislocation resistivity, the thermoelectric characteristic of dislocations shows high sensitivity to change of the width of the resonance level and its localization relative to the Fermi energy. A model dislocation potential is suggested; with it, a rather good agreement with available experimental data is obtained.
Schoen's augmented-plane-wave virtual-crystal approximation (APW-VCA) is used first for calcu lation of the density of electronic states and electronic properties of disordered substitutional metal alloys. The electronic specific heat coefficient and the diffusion thermopower of Ag,Pdi_^ and C ujN ii-j alloys as a function of concentration are calculated. The calculation used no adjustable parameters. The results are compared with experiment and with previous calculations performed in the framework of CPA. It is shown that the agreement with experiment is not worse than within CPA, and at a low concentration of the noble metal it is even better. Приближение виртуального кристалла Шоена на базе метода присоединенных плоских волн (ППВ-ПВК) использовано впервые для расчета плотности электронных состояний и электронных свойств неупорядоченных металлических сплавов замещения. Рассчитаны коэффициент электронной удельной теплоемкости и диффузионная термо ЭДС сплавов AgjPdi-j и QijNii-jr как функция концентрации. Расчет не содержит подгоночного пара метра. Результаты расчета сравниваются с экспериментом и расчетами, выполненными в ItlKJI. Показано, что согласие с экспериментом получено не хуже, чем с использованием ПКП, а при низкой концентрации благородного металла, даже лучше.
The thermopower induced by tensile plastic deformation at a near-room temperature is measured to determine the change in thermopower per unit dislocation density S d /N d in nickel (99.98%). The dislocation density is determined indirectly by measurement of the flow stress. The partial-wave method is used to calculate the contribution of dislocations and vacancies to the thermoelectric power of nickel, platinum and palladium. The value S d /N d calculated for nickel agrees quite satisfactorily with measured ones. These results are the first quantitative estimation of the defect contribution to thermopower of transition metals.
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