Studies of Stress and Fatigue Induced Defects Using Small Angle Neutron Scattering

摘要

The technique of small angle neutron scattering (SANS) is proving to be of great value in the study of deformation-induced defects in various materials. Frequently SANS is the only practicable method for obtaining detailed, quantitative information on the kinetics of defect production. In crystalline material, the following defects produced by deformation are most amenable to study by SANS: bulk microcracking in brittle material; voids, bubbles and vacancy clusters; dislocations. If a broad definition is adopted for the types of defects to be considered, we can include the accelerated coarsening of particles and precipitates produced by high temperature deformation. To date the greatest success with SANS in the study of defects associated with stress has been achieved with cavities (voids, etc.) and microcracks. The presence of dislocations can be detected by neutron scattering, but more extensive data on their nature, disposition and density usually can be obtained readily by TEM examination of thin foils. Accordingly, emphasis in this review is on those defects for which neutron scattering has yielded detailed information not readily available by other methods. 32 refs., 7 figs. (ERA citation 11:020246)