Shaping advanced ceramics with electrical discharge machining /
| Main Author: | |
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| Other Authors: | , , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1989.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | The objective of the proposed research is top apply electrical discharge machining (EDM) to the fabrication of ceramics. The maximum electrical resistivity required for cutting was found to be 100 Ω cm. Operating conditions were determined and optimized for a number of ceramic materials which meet the criteria. Two single-phase ceramics and nine composite-ceramics were studied. The cutting mechanism for each material was determined by using electron microscopy. Cutting occurs due to either melting or thermal spalling. Dimensional analysis was used to correlate cutting characteristics to material properties and very rough correlations were obtained for material removal rate and surface roughness. It was observed that as energy per unit volume decreased, the material removal rate increased. Various analytical techniques were performed to study the surface changes, such as x-ray diffraction, x-ray photoelectron spectroscopy, and Vicker's microhardness tests. Many surface changes were found to occur for the various composites EDMed. Some showed preferential oxidation, such as SiC-TiB₂. The materials which spalled increased in hardness slightly while those that melted decreased in hardness. Limited contamination of all samples by the cutting electrode (wire) and the dielectric fluid was observed. X-ray diffraction was used to determine the residual surface stress in TiB₂ and B₄C cut by EDM and diamond saw. The results are in accordance with the hardness of these surfaces. In both cases EDMing creates larger stresses normal to the machining direction than those created in the machining direction.. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Chemical engineering." |
| Physical Description: | xiii, 105 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |