Mechanical behavior of MoSi2 reinforced-Si3N4 matrix composites

The mechanical behavior of MoSi2 reinforced Si3N4 matrix composites was investigated as a function of MoSi2 phase content, MoSi2 phase size, and amount of MgO densification aid for the Si3N4 phase. Coarse-phase MoSi2-Si3N4 composites exhibited higher room temperature fracture toughness than fine-pha...

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Veröffentlicht in:Journal of the American Ceramic Society 1997-12, Vol.80 (12), p.3070-3076
Hauptverfasser: PETROVIC, J. J, PENA, M. I, REIMANIS, I. E, SANDLIN, M. S, CONZONE, S. D, KUNG, H. H, BUTT, D. P
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Sprache:eng
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Zusammenfassung:The mechanical behavior of MoSi2 reinforced Si3N4 matrix composites was investigated as a function of MoSi2 phase content, MoSi2 phase size, and amount of MgO densification aid for the Si3N4 phase. Coarse-phase MoSi2-Si3N4 composites exhibited higher room temperature fracture toughness than fine-phase composites, reaching values greater than 8 MPa sq rt m. Composite fracture toughness levels increased at elevated temperature. Fine-phase composites were stronger and more creep resistant than coarse-phase composites. Room temperature strengths greater than 1000 MPa and impression creep rates of 10 exp -8/s at 1200 C were observed. Increased MgO levels generally were deleterious to MoSi2-Si3N mechanical properties. Internal stresses due to MoSi2 and Si3N4 thermal expansion coefficient mismatch appeared to contribute to fracture toughening in MoSi2-Si3N4 composites. (Author)
ISSN:0002-7820
1551-2916
DOI:10.1111/j.1151-2916.1997.tb03234.x