Effects of ZrO2 addition on microstructure and mechanical properties of MoSi2
Effects of ZrO2 addition on microstructure and mechanical properties of MoSi2
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DOI：
10.1016/0956-716x(95)00093-b
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发表时间：
1995-07
期刊：
影响因子：
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通讯作者：
Yoshikazu Suzuki;T. Sekino;K. Niihara
中科院分区：
文献类型：
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作者：
Yoshikazu Suzuki;T. Sekino;K. Niihara
采用常规热压法制备了添加MoSi{sub 2}的3Y-ZrO{sub 2}基复合材料。这些复合材料主要由基体MoSi{sub 2}、结晶良好的ZrSiO{sub 4}、Mo{sub {<=}5}Si{sub 3}C{sub{<=}1}和未反应的四方体ZrO{sub 2}组成。通过添加3Y-ZrO{sub 2}，晶间玻璃态SiO{sub 2}相转变为热力学稳定的ZrSiO{sub 4}晶相。3Y-ZrO{sub 2}的加入提高了材料的室温断裂韧性和强度等力学性能。MoSi{sub 2}-3Y-ZrO{sub 2}体系断裂韧性的增强主要是由于晶界处脆性玻璃态SiO{sub 2}相的减少以及MoSi{sub 2}与ZrSiO{sub 4}热膨胀系数不匹配导致的残余压应力的减少。这些结果表明，添加3Y-ZrO{sub 2}使玻璃态sio2相原位结晶，有利于制备力学性能平衡的MoSi{sub 2}基复合材料。进一步优化制备条件可以提高MoSi{sub 2}-ZrO{sub 2}体系的力学性能。
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.