Accession Number : AD0257188

Title :   THE EFFECT OF PLASTIC DEFORMATION ON SELF - DIFFUSION IN NICKEL

Corporate Author : MATERIALS RESEARCH LAB UNIV OF CALIF BERKELEY

Personal Author(s) : WAZZAN,A.R. ; MOTE,J. ; DORN,J.E.

Report Date : 18 APR 1961

Pagination or Media Count : 1

Abstract : The coefficient of self-diffusion in nickel single crystals in the unstrained state was found to be a function of temperature. The coefficient of self-diffusion of Ni single crystals undergoing plastic deformation (tensile) was measured for strain rates ranging from 0.0085 to 0.055/hr at 948 + or - 1.5 K and 1021 + or - 1.5 K. It was found that the coefficient of self-diffusion increased with an increase in strain rate at a constant temperature and decreased with an increase in temperature at constant strain rate. These results are discussed in terms of a model which assumes that vacancies are produced by two mechanisms, namely, the motion of jogged screw dislocations and the thermally activated climb of edge dislocations and that vacancies anneal by migrating to fixed sinks, namely, dislocation lines. The analysis indicates that the motion of jogged screws may be an unimportant source for vacancies at these temperatures and strain rates. (Author)

Descriptors :   *DIFFUSION, *NICKEL, *SINGLE CRYSTALS, DEFORMATION, ELECTRON TRANSITIONS, ELECTROPLATING, ISOTOPES, METAL CRYSTALS, PLASTIC PROPERTIES, RADIOACTIVE ISOTOPES, STRESSES, TEMPERATURE, TRACER STUDIES

Distribution Statement : APPROVED FOR PUBLIC RELEASE