TOUGHENING MECHANISMS IN THE HIGH-TEMPERATURE FRACTURE OF HIGH-PURITYALUMINA

Authors
MARROW TJ ROBERTS SG
Citation
Tj. Marrow et Sg. Roberts, TOUGHENING MECHANISMS IN THE HIGH-TEMPERATURE FRACTURE OF HIGH-PURITYALUMINA, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 176(1-2), 1994, pp. 455-460
Citations number
40
Categorie Soggetti
Material Science
Journal title
Materials science & engineering. A, Structural materials: properties, microstructure and processing → ACNP
ISSN journal
09215093
Volume
176
Issue
1-2
Year of publication
1994
Pages
455 - 460
Database
ISI
SICI code
0921-5093(1994)176:1-2<455:TMITHF>2.0.ZU;2-4
Abstract
The R curve behaviour of long cracks in high purity (99.98%) polycryst alline alumina was investigated using a single-edge precracked beam, a t room temperature, 900 degrees C and 1200 degrees C. The room tempera ture R curve was negligible. A strong R curve was observed at 900 degr ees C and 1200 degrees C. This was associated with a change in slow cr ack growth mode from mixed intergranular fracture and transgranular cl eavage to fully intergranular fracture. Scanning acoustic microscopy c onclusively demonstrated asperity contact in the crack wake at high te mperature. It is proposed that the high temperature R curve behaviour is due to crack shielding from friction in the crack wake.