Accession Number : AD0270245

Title :   RELATION OF DISLOCATION DENSITY TO THE YIELD STRESS OF COPPER CRYSTALS

Corporate Author : WATERVLIET ARSENAL N Y

Personal Author(s) : HORDON,M.J.

Report Date : OCT 1961

Pagination or Media Count : 1

Abstract : Measurements of the dislocation density by a chemical etching technique in high-purity copper single crystals were related to applied flow stress and yield stress. The results were interpreted by the model of Seeger for pure metals in which the flow stress consists of a temperature, strain rate dependent component arising from the thermally activated motion of glide dislocations, and a dislocation dependent component arising from the elastic stress interactions of glide dislocations. The activation energy calculated from the forest mechanism was 0.9 ev, consistent with the formation energy of jogs due to dislocation intersection. The flow stress was found to increase parabolically with dislocation density in accord with the Seeger model. Observations of individual dislocation motion and mechanical polygonization after plastic stress were also made. (Author)

Descriptors :   *COPPER, *SINGLE CRYSTALS, *STRESSES, CREEP, CRYSTAL LATTICES, MATHEMATICAL ANALYSIS, PLASTIC PROPERTIES, SHEAR STRESSES, TEMPERATURE, THEORY

Distribution Statement : APPROVED FOR PUBLIC RELEASE