Abstract
Partial reduction reactions were used to form a metallic phase either around or inside oxide grains in polycrystals in the FeMnO system. By suitable choice of oxide composition, partial pressure of oxygen, annealing time and temperature, it is possible to control the nucleation and growth of the metallic phase to produce a wide range of metal-ceramic microstructures. These include ceramic grains with a thin layer of metallic phase at their boundaries; ceramic grains with a thick layer of metallic phase at their boundaries -essentially, a metal-ceramic composite; and ceramic grains containing a fine distribution of metal particles-essentially, a ductile phase toughened ceramic. The presence of the metallic phase increases the fracture toughness of all the metal-ceramic microstructures with respect to that of the pure ceramic, with the largest increase observed for the metal-ceramic composite. It is believed that the principles established by studying the FeMnO system can be used on more practical mixed oxide systems to produce metal-ceramic microstructures, which in some cases are unique, and in particular, if the starting oxide material is in the form of plate- or rod-shaped crystals, to produce metal-ceramic composites in situ.
| Original language | English |
|---|---|
| Pages (from-to) | 2153-2161 |
| Number of pages | 9 |
| Journal | Acta Metallurgica et Materialia |
| Volume | 41 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - Jul 1993 |
| Externally published | Yes |
Funding
Acknowledgements--The initiation of this research was supported by the Office of Naval Research under Grant N00014-91-J-1660, the U.S. Department of Energy under Grant DE-FG02-88ER45357 and the National Science Foundation through Materials Science Center of Cornell University, Grant DMR-88-18558. Current support is provided by the Office of Naval Research under Grant N00014-92-J-1526. The use of the Electron Microscopy and Materials Preparation Facilities of the Materials Science Center at Cornell University is gratefully acknowledged. Discussions with Dr D. S. Farquhar on the interpretation of the hardness measurements in terms of fracture toughness were stimulating and invaluable. Finally, the assistance of Professor W. Sachse and Dr M. Veidt in making the Young's modulus measurements was greatly appreciated.
| Funders | Funder number |
|---|---|
| Materials Science Center of Cornell University | DMR-88-18558, N00014-92-J-1526 |
| National Science Foundation | |
| Office of Naval Research | N00014-91-J-1660 |
| U.S. Department of Energy | DE-FG02-88ER45357 |