Radial variations in fracture and acoustic emission of a thermic graphite electrode

✍ Scribed by Youfa Yin; Robin G. Cooke; Brian McEnaney

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 535 KB
• Volume: 29
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(91)90039-l

✦ Synopsis

an extruded electrode graphite, grain orientation increases and porosity decreases with increasing radial distance from the centre of the log. Radial variation in grain orientation is produced during the extrusion stage of manufacture. The radial porosity gradient may be influenced partly by orientation of grains and also by the impregnation and baking stages of manufacture. Dynamic elastic modulus, flexural strength, and critical stress intensity factor increase with distance from the centre of the log; these trends are related to the radial porosity gradient. Fracture toughness and the total number of acoustic emissions at fracture, &, are insensitive to graphite microstructure. Fracture of the graphite is non-linear and deviations from linear elastic fracture mechanics increase with distance from the centre of the log, a trend which is related to the radial porosity gradient. An empirical correlation between a non-ideal fracture parameter and H AE is demonstrated for the electrode graphite and three nuclear graphites.