Accession Number : AD0432504


Title :   RESEARCH ON THE MECHANISMS OF FATIGUE.


Descriptive Note : Rept. for 1 Dec 61-31 Aug 63,


Corporate Author : MIDWEST RESEARCH INST KANSAS CITY MO


Personal Author(s) : Grosskreutz,J C


Report Date : Dec 1963


Pagination or Media Count : 117


Abstract : The accumulation of fatigue damage was studied on a microscopic scale in polycrystalline aluminum cycled at constant strain. At moderate strain amplitudes, the dominant feature is a subgrain structure which originates with the clustering of dislocations into sub-boundaries during the first few hundred cycles of strain. At low strains, large concentrations of dislocation loops are formed, either near subgrain boundaries, or on glide planes in areas devoid of subgrains. These observations were used to construct a model of fatigue hardening which agrees with the published hardening curves for aluminum. (Author)


Descriptors :   *FATIGUE(MECHANICS) , *ALUMINUM , METALLOGRAPHY , GRAIN STRUCTURES(METALLURGY) , FRACTURE(MECHANICS) , ELECTRON MICROSCOPY , X RAY DIFFRACTION , HARDNESS , COATINGS , EPOXY RESINS , COPPER ALLOYS , ZINC ALLOYS , CRYOGENICS


Distribution Statement : APPROVED FOR PUBLIC RELEASE