Compressive creep of mullite containing Y2O3

✍ Scribed by A.R de Arellano-López; J.J Meléndez-Martínez; T.A Cruse; R.E Koritala; J.L Routbort; K.C Goretta

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 489 KB
• Volume: 50
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/s1359-6454(02)00264-1

✦ Synopsis

Compressive creep of mullite and mullite containing 5 and 9 wt% Y 2 O 3 has been investigated in the temperature range of 1300-1400 °C over stresses between Ϸ0.6 and 40 MPa in air. The nominally single-phase mullite deforms by diffusional flow with a stress exponent of 1 (for higher stresses) and an activation energy of 385 ± 20kJ / mol. It is likely that the rate-controlling diffusing species is oxygen. Creep of the Y 2 O 3 -containing specimens was similar to that of the pure mullite at 1300 °C. Near and above the temperature at which melting was observed in DTA, the Y 2 O 3containing specimens crept significantly faster than the pure mullite. Models of creep of materials that contain a glass phase can explain most, but not all, of the observed behavior. Creep rates were not significantly affected by partial crystallization of the glass to Y 2 Si 2 O 7 , but the crystallized specimens exhibited cavitation at larger strains.