Accession Number : AD0290692

Title :   A NEW THEORY OF WORK HARDENING IN CRYSTALS

Corporate Author : PENNSYLVANIA UNIV PHILADELPHIA

Personal Author(s) : KUHLMANN-WILSDORF,D.

Report Date : SEP 1962

Pagination or Media Count : 1

Abstract : The three stages of the usual work hardening curve of fcc metals, easy glide, stage II, and stage III, are examined theoretically. The manifold and complex observations regarding easy glide may be understood from the idea that easy glide is the stage during which dislocations move and multiply, spreading throughout the specimen until a quasi-uniform dislocation density, commensuate with the applied stress, has been established. The cause for the amazingly consistent ratio of theta sub II, the work-hardening coefficient during stage I, to G, the modulus of rigidity, such that B/theta sub II = k is about 300 is investigated. Stage II is explained on the basic assumption that multiplcation and movements of dislocations take place in such a manner that the dislocation configuraions first established change in scale only, but not in character. Stage III is understood to commence at the onset of additional modes of islocation motion, besides slip, be it climb, or cross slip or both. The dislocation pattern then changes in character. (Author)

Descriptors :   *METAL CRYSTALS, CRYSTAL DEFECTS, CRYSTALS, DEFORMATION, HARDENING, THEORY

Distribution Statement : APPROVED FOR PUBLIC RELEASE