Microstructure and mechanical properties of MoSi{sub 2}/SiC composites
- Osaka Univ., Ibaraki (Japan)
Microstructure effects on mechanical properties were investigated for SiC particulate reinforced MoSi{sub 2} composites. These composites were prepared by hot-pressing mixtures of sub-micron MoSi{sub 2} and nano-sized SiC powders at 1300 to 1800{degrees}C in Ar atmosphere. The microstructure of MoSi{sub 2}-based composites consisted of MoSi{sub 2}, SiC and small amounts of Mo{sub 5}Si{sub 3} and Mo{sub 2}C. Transmission electron microscopic observation revealed that the nano-sized {beta}-SiC particles were dispersed at the grain boundaries and also within the MoSi{sub 2} matrix grains. The fracture strength and toughness were considerably improved by the SiC dispersions. The MoSi{sub 2}/15vol%SiC composite hot-pressed at 1500{degrees}C gave the maximum strength of 1215 MPa. The enhancement of fracture strength in this system was mainly caused by the grain growth inhibition by the SiC dispersion. Moreover, the intergranular SiC particles played important roles to control the grain boundary structure by connecting directly with the matrix MoSi{sub 2} grains without impurity phases.
- OSTI ID:
- 62855
- Report Number(s):
- CONF-940315--; CNN: Grant 03555157; Grant 04205099
- Country of Publication:
- United States
- Language:
- English
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