Effects of ZrO{sub 2} addition on microstructure and mechanical properties of MoSi{sub 2}
- Osaka Univ., Ibaraki (Japan). Inst. of Scientific and Industrial Research
Fine 3Y-ZrO{sub 2} added MoSi{sub 2}-based composites were fabricated by the conventional hot-pressing method. These composites mainly consisted of matrix MoSi{sub 2}, well-crystallized ZrSiO{sub 4}, Mo{sub {<=}5}Si{sub 3}C{sub {<=}1} and non-reacted tetragonal ZrO{sub 2}. The intergranular glassy SiO{sub 2} phase could be changed into the thermodynamically stable ZrSiO{sub 4} crystalline phase by the 3Y-ZrO{sub 2} addition. Mechanical properties at room temperature such as fracture toughness and strength were enhanced by the 3Y-ZrO{sub 2} addition. The enhancement of fracture toughness in the MoSi{sub 2}-3Y-ZrO{sub 2} system was attributed mainly to the decrease of the brittle glassy SiO{sub 2} phase at grain boundaries and the residual compressive stresses induced by the mismatch of thermal expansion coefficient between MoSi{sub 2} and ZrSiO{sub 4}. These results indicate that in-situ crystallization of the glassy SiO 2 phase by the addition of 3Y-ZrO{sub 2} has great advantage to fabricate MoSi{sub 2}-based composites with well-balanced mechanical properties. Further optimization of fabrication conditions will enable one to improve the mechanical properties of MoSi{sub 2}-ZrO{sub 2} system.
- OSTI ID:
- 99231
- Journal Information:
- Scripta Metallurgica et Materialia, Journal Name: Scripta Metallurgica et Materialia Journal Issue: 1 Vol. 33; ISSN SCRMEX; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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