A Technique for producing Regular Patterns on Single Crystals

Abstract

TO examine the deformation of single crystals, it is often necessary to have regularly spaced marks or a grid on the surface of the specimen. In particular, the analysis of plastic strains is carried out by investigating the distortion of the grid using the intersections of the lines as reference points. There are several methods for producing a grid, but usually only one of the following two is used: (1) scratching accurately spaced lines; (2) photo-engraving the required pattern. Both are laborious and require great care in their application. All the methods known to authors subject the specimen to a certain amount of deformation. This affects only the surface of a polycrystalline specimen and can be completely disregarded except when the surface processes themselves are investigated. On the other hand, the mechanical properties of single crystals are extremely sensitive to surface effects. On this account, none of the existing methods was considered satisfactory. It is the purpose of this communication to report a technique which was developed for producing regular patterns on single crystals without subjecting the specimen to any strain.