Accession Number : AD0673349

Title :   FLOW AND FRACTURE OF MOLYBDENUM UNDER SPACE VACUUMS,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Feuerstein,Seymour

Report Date : JUN 1968

Pagination or Media Count : 30

Abstract : A model is postulated that accounts for the low-pressure-dependent ductility effect in bulk polycrystalline molybdenum deformed in tension at ambient temperature; a hydrogen type of embrittlement mechanism is proposed. This model is based on experimental data. The vacuum dependence of specimen ductility is related to the rate of gaseous monolayer coverage and subsequent surface diffusion of mobile atoms onto available atomic sites. This occupation of free atomic sites, in turn, impedes the release (also by diffusion) of contaminant gases from within the material and results in large internal pressures at crack sites at or near the surface. (Author)

Descriptors :   (*MOLYBDENUM, MECHANICAL PROPERTIES), DUCTILITY, HYDROGEN EMBRITTLEMENT, VACUUM, SURFACE PROPERTIES, DIFFUSION, GASES, CONTAMINATION, FRACTURE(MECHANICS), PRESSURE, DISLOCATIONS, ADSORPTION, SPACE ENVIRONMENTS, RHEOLOGY

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE