TOUGHENING MECHANISMS IN THE HIGH-TEMPERATURE FRACTURE OF HIGH-PURITY ALUMINA

Conference item

The R curve behaviour of long cracks in high purity (99.98%) polycrystalline alumina was investigated using a single-edge precracked beam, at room temperature, 900 °C and 1200 °C. The room temperature R curve was negligible. A strong R curve was observed at 900 °C and 1200 °C. This was associated with a change in slow crack growth mode from mixed intergranular fracture and transgranular cleavage to fully intergranular fracture. Scanning acoustic microscopy conclusively demonstrated asperity contact in the crack wake at high temperature. It is proposed that the high temperature R curve behaviour is due to crack shielding from friction in the crack wake. © 1994.

Authors: Marrow, T; Roberts, S

• Publication status: Published
• Journal: MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
• Volume: 176
• Issue: 1-2
• Pages: 455-460
• Publication date: 1994-03-31
• Event title: 36th Yamada Conference/International Conference on Fundamentals of Fracture
• DOI: 10.1016/0921-5093(94)91014-6
• ISSN: 0921-5093
• Keywords: DEFORMATION; RESISTANCE; ELEVATED-TEMPERATURES; POLYCRYSTALLINE ALUMINA; R-CURVE BEHAVIOR; BRITTLE MATERIALS; CRACK-GROWTH; GRAIN-SIZE; CERAMIC MATERIALS; DEPENDENCE