采用湿法混合和热压工艺制备了不同Si3N 4(p)和SiC (w)体积含量的MoSi 2基复合材料, 研究了复合材料的显微组织、晶粒大小、硬度、断裂韧性和抗弯强度. 结果表明, 复合材料的晶粒比纯MoSi 2明显细化, 且随着强化相添加量的增加而减小, 抗弯强度和断裂韧性均大幅度提高, 其中MoSi 2--20%SiC (w) --20%Si 3N 4(p)复合材料具有较好的综合力学性能, 断裂韧性和抗弯强度分别427 MPa和10.4 MPa ? m1/2. 复合材料的强化机制为细晶强化和弥散强化, 韧化机制为细晶韧化和裂纹偏转与分支韧化.
MoSi2 composites with different Si 3N 4(p) and SiC(w) volume contents are prepared by means of wet mixing and heat pressing process. The morphology, grain size, hardness, fracture toughness, bending strength of the MoSi2–Si3N4(p)/SiC(w) composites were investigated by means of scanning electron microscope (SEM), polarizing microscopy, vickers hardness tester, and universal material testing machine in this paper. It is shown that mechanical properties of the prepared composites are much higher than that of MoSi2, and its grain size is finer than that of MoSi2, more over it is declined with the increasing of strengthening phases. MoSi2–20% Si3N4(p)–20% SiC(w) composite has better mechanical properties, and its bending strength and room fracture toughness are 427 MPa and 10.4 MPa·m1/2, respectively. The strengthening mechanism of MoSi2– Si3N4(p)/SiC(w) composites are fine grain strengthening and dispersion strengthening, and the toughening mechanism are fine grain toughening and crack deflection toughening.
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