Small angle neutron scattering study of fatigue induced grain boundary cavities
Small angle neutron scattering (SANS) has been used to study grain boundary cavitation in high purity copper fatigued at elevated temperatures. SANS is an extremely sensitive method for observing cavities. Void volume fractions of less than 10/sup -6/ can be detected. Analysis of scattering data yields values for the total void volume per unit volume and the total number of voids in a fatigued sample. The size distribution of the voids also can be calculated. From a series of specimens, each fatigued under identical conditions but for varying lengths of time, it is possible to obtain the void nucleation rate and the rate of growth of the total void volume and of the individual voids. Extrapolation of curves of void volume fraction vs time of fatigue to zero time shows that cavitation begins upon commencement of fatiguing without any measurable incubation time. Void nucleation is continuous throughout fatigue Calculated values of the individual void growth rate agree very well, as regards time dependence, temperature dependence, and even absolute value, with growth rates derived from a theory of fatigueinduced cavitation based on transient effects in vacancy diffusion.
- Research Organization:
- Southwest Research Institute, 6220 Culebra Road, P.O. Drawer 28510, San Antonio, TX 78284
- OSTI ID:
- 5962722
- Journal Information:
- Acta Metall.; (United States), Vol. 30:7
- Country of Publication:
- United States
- Language:
- English
Similar Records
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Related Subjects
CAVITATION
SMALL ANGLE SCATTERING
COPPER
GRAIN BOUNDARIES
THERMAL FATIGUE
DATA ANALYSIS
INTERGRANULAR CORROSION
NEUTRON DIFFRACTION
NUCLEATION
VOID FRACTION
CHEMICAL REACTIONS
COHERENT SCATTERING
CORROSION
CRYSTAL STRUCTURE
DIFFRACTION
ELEMENTS
FATIGUE
MECHANICAL PROPERTIES
METALS
MICROSTRUCTURE
SCATTERING
TRANSITION ELEMENTS
360103* - Metals & Alloys- Mechanical Properties