Unified interpretation of internal stress superplasticity models based on thermally- activated kinetics

✍ Scribed by K. Kitazono; E. Sato; K. Kuribayashi

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 217 KB
• Volume: 47
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/s1359-6454(98)00431-5

✦ Synopsis

have been expanded to include the temperature dependence of the average strain rate. It is revealed that the constitutive equations of these models are equivalent regarding the thermally activated kinetics, and that the apparent activation energy of internal stress superplasticity is equal to 1/n (where n is the stress exponent of isothermal power-law creep) times that of isothermal power-law creep. This theoretical prediction has been experimentally veri®ed by the thermal cycling creep tests using the same temperature pro®les with several equivalent temperatures in a Be particle-dispersed Al matrix composite. The obtained apparent activation energy was 22 kJ/mol, which is approximately 1/7 times that of isothermal creep.