Kriterium der Gleitbereitschaft metallischer Vielkristalle

Summary

The first section of the paper is devoted to a brief discussion of some principles of the electron theory of metals, which show that there are no definite localized bonds between any definite atoms of the metallic lattice. Slip is possible without any bonds being disrupted or even any energy spent against bonding forces. In a crystallite making part of a polycrystal slip is possible as soon as the elastic strain energy can, by slipping, be reduced. On this assumption and taking into consideration elastic and plastic transverse contractions a stress value is derived, which can be considered as a lower limit for the advent of slip. It is inversely proportional to the diameter of the crystallite or more exactely to the free path of slip and to some extent dependent onPoisson's ratio. Determinations of the elastic limit of wrought and of sintered pure aluminium samples are given and shown to be in accordance with this theory.