Quadrupole Broadening of Nuclear Magnetic Resonance Lines in Deformed Copper and Aluminum

The nuclear magnetic resonance lines of Cu 63 and Al 27 in bulk polycrystalline copper and aluminum have been measured as a function of plastic deformation. The line shape of these signals shows a quadrupolar broadening from which the mean dislocation density of the deformed samples may be determined. It was found that in each the flow stress which is effective during the deformation is proportional to the square root of the dislocation density. — The NMR signal of a plastically deformed copper single crystal shows a dependence of the quadrupole perturbation on the direction of the external magnetic field H 0 relative to the crystal axes. This results can be explained on the basis of the special position of the dislocations in the lattice.