Accession Number : ADA016133


Title :   The Diffusion of Antimony of Alpha Iron.


Descriptive Note : Final rept.,


Corporate Author : ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN MASS


Personal Author(s) : Bruggeman,Gordon A.


Report Date : AUG 1975


Pagination or Media Count : 14


Abstract : Diffusion coefficients of antimony in alpha iron were determined in the temperature range 700 to 900C using the residual activity method. Specimens were large-grained polycrystals for the higher temperature measurements and single crystals for the lower temperature measurements. The activation energy (reported in calories/mole) is approximately equal to that measured for iron self-diffusion in this same temperature range, although the antimony diffusion coefficients are a factor of ten larger than the iron self-diffusion coefficients. The potential for strongly coupled vacancy-antimony motions is demonstrated, based on the observed enhancement of iron self-diffusion in dilute iron-antimony alloys. Finally, molybdenum is shown to have a negligible effect on the diffusion of antomony in alpha iron. These results are discussed in relation to the phenomenon of temper brittleness in steels. Embrittlement kinetics in iron-antimony alloys are shown to be consistent with an antimony diffusion-controlled segregation mechanism.


Descriptors :   *IRON, *DIFFUSION, *ANTIMONY, REACTION KINETICS, HIGH TEMPERATURE, EMBRITTLEMENT, IMPURITIES, STEEL, CRYSTAL DEFECTS, TRACER STUDIES, ACTIVATION ENERGY.


Subject Categories : METALLURGY AND METALLOGRAPHY


Distribution Statement : APPROVED FOR PUBLIC RELEASE