Optical Probing of Acoustic Emission During Deformation of Microtensile Specimens.
Abstract
Optical interferometric techniques were adapted to detect and analyze acoustic emission signals from 304L stainless steel. The objective of this study was to determine the correlation between fracture surface topography and acoustic emission signals emitted by the material during plastic deformation and failure, and to reconcile this information with existing theories of acoustic emission generation in polycrystalline materials. A pneumatic load system was developed to accept an optical interferometer as the device for detecting acoustic emission signals. Microtensile specimens were fabricated which limited the zone of deformation to approximately three cubic millimeters in volume. Use of the optical probe permitted the monitoring of transient surface displacements at locations within fractures of a millimeter of the deforming volume. Results demonstrate that acoustic emission is a volume phenomena. For the small plastic zone size investigated, the acoustic emission counts have been minimized to the extent that signals are separated in time and waveform analysis can be conducted on each of the signals. Test results show that models describing dislocations as the sources of acoustic emission are not sufficient to describe the observed behavior. Keywords: Acoustic Emission, Stainless Steel, Fracture, Non-Destructive Testing, Failure, Materials.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1986
- Accession Number
- ADA177576
Entities
People
- William J. Bruchey Jr.
Organizations
- Ballistic Research Laboratory