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U.S. Department of Energy
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A study of mechanical processing damage in brittle materials. Annual progress report, 1 April 1988--31 March 1989

Technical Report ·
DOI:https://doi.org/10.2172/10155303· OSTI ID:10155303
The first project deals with examining ceramics when they are in the green state, and evaluating the effect of density and mechanical property variations on the final hot-pressed parts. The second aspect of the project deals with the direct characterization of surface and near-surface defects that are induced by machining operations. For the ultrasonic inspection of green ceramics, it is necessary to introduce ultrasound in the sample without immersing it in water. The author`s approach is to develop air transducers based on using new types of matching layers. The paper describes the development of these air transducers. The work on the characterization of machining damage in ceramics considered the special problem of ball bearings. Ball bearings may be the first wide-range industrial application for hot-pressed ceramic materials. The major problem with the ball bearings is their sensitivity to small surface and near-surface defects. Presently, inspection is performed by optical microscopy. The author developed an amplitude and phase acoustic microscopy method and constructed a special fixture to rotate the ball bearings under a focused transducer.
Research Organization:
Stanford Univ., CA (United States). Edward L. Ginzton Lab.
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
FG03-84ER45157
OSTI ID:
10155303
Report Number(s):
DOE/ER/45157--T5; ON: DE94012348; BR: KC0201050
Country of Publication:
United States
Language:
English