High-temperature compressive creep of liquid phase sintered silicon carbide

Journal Article · Fri May 28 04:00:00 EDT 1999 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(99)00072-5· OSTI ID:357931

Gallardo-Lopez, A; Munoz, A; Martinez-Fernandez, J; Dominguez-Rodriguez, A ^[1]

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1. Univ. de Sevilla (Spain). Dept. de Fisica de la Materia Condensada

Creep of liquid phase sintered SiC has been studied at temperatures between 1,575 and 1,700 C in argon under nominal stresses from 90 to 500 MPa. Creep rates ranged from 3 {times} 10{sup {minus}8} to 10{sup {minus}6}/s, with an activation energy of 840 {+-} 100 kJ/mol (corresponding to carbon and silicon self-diffusion), and a stress exponent of 1.6 {+-} 0.2. The crept samples showed the presence of dislocation activity, generally forming glide bands and tangles. Degradation of the mechanical properties due to cavitation or reaction of the additives was not detected. SEM and TEM microstructural characterization and analysis of the creep parameters leads to the conclusion that the creep mechanisms operating are grain boundary sliding accommodated by lattice diffusion and climb-controlled dislocation glide operating in parallel. Other possible operating mechanisms are discussed and the data are compared with published data.

• OSTI ID: 357931
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 7 Vol. 47; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
CREEP
DIFFUSION
DISLOCATIONS
ELECTRON MICROSCOPY
MICROSTRUCTURE
SILICON CARBIDES
TEMPERATURE RANGE 1000-4000 K