A Calculation of the Changes in the Conductivity of Metals Produced by Cold-Work

The increase in the electrical resistance of severely cold-worked metals has been calculated by assuming that the important change which occurs during cold-work is the introduction of large numbers of Taylor dislocations. The results obtained are as follows: The calculated increase in the electrical resistance of polycrystalline copper is in good agreement with the measured value. In case single crystals are considered, the calculations show that there is a decided dependence of the dislocation resistance on the orientation of the electric field relative to the crystallographic axes. In copper the ratio of the largest dislocation resistance to the smallest is 8. This ratio is large for materials having a small Poisson's ratio. It is found that if the dislocations are not too closely clustered no interference effects will occur. The detailed calculations for copper assume that clustering is unimportant. Measurements on single crystals are in progress.