The surface structure of gallium after plastic deformation by unidirectional abrasion and by rolling

Abstract

Electron diffraction at grazing incidence shows that the preferred one-degree crystal orientations developed in the surface region of gallium by unidirectional abrasion and by rolling are of the same type. A [100] axis is normal to the specimen surface or nearly so, possibly together with some [010] orientation, relative to the axes a=4·5107, b=4·5167, c=7·6448 Å. This [100] orientation appears to be analogous to the [001] orientation observed on graphite after abrasion, in that the Ga atoms in the (100) planes form plane networks of linked hexagons.Unidirectional abrasion of a Ga single crystal on 4/0 emery paper resulted in only a small amount of Ga in the above one-degree orientation at the surface. Most of the surface Ga retained either the initial single-crystal orientation or a range of orientations obtained from this by rotation (up to about 10°) about an axis parallel to the surface and normal to the abrasion direction, as is typical of the `transition region' in other abraded metal crystals.