(1. 湖南科技大學(xué) 先進材料制備及應(yīng)用技術(shù)研究所，湘潭 411201；
2. 中南大學(xué) 粉末冶金國家重點實驗室，長沙 410083)
摘 要: 以MoSi2、Ti和B4C粉為原料，采用高溫?zé)釅杭夹g(shù)合成不同體積分數(shù)TiC-TiB2增強MoSi2復(fù)合材料，研究TiC-TiB2顆粒對MoSi2基體材料顯微組織、力學(xué)性能和高溫氧化性能的影響。結(jié)果表明：30%TiC-TiB2/MoSi2(體積分數(shù))復(fù)合材料的抗彎強度和維氏硬度分別達到468.3 MPa和17.07 GPa，比純MoSi2的分別增加了63.2%和83.5%。隨著TiC-TiB2體積分數(shù)的增加，復(fù)合材料的斷裂方式由以沿晶斷裂為主向以穿晶斷裂為主轉(zhuǎn)變，強化機制是細晶強化和彌散強化。在800~1 200 ℃氧化192 h時，30%TiC-TiB2復(fù)合材料的增質(zhì)是10%TiC-TiB2復(fù)合材料的2.38~3.23倍。氧化層中沒有發(fā)現(xiàn)低熔點的B2O3，而TiO2和SiO2的存在使材料具有較好的抗氧化性。
關(guān)鍵字: MoSi2；復(fù)合材料；TiC；TB2；力學(xué)性能；氧化行為
TiC-TiB2 reinforced MoSi2 composites
（1. Institute of Advanced Materials Synthesis and Application Technology, Hunan University of Science and Technology, Xiangtan 411201 China;
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:TiC-TiB2/MoSi2 composites with different volume fractions of TiC-TiB2 particles were fabricated by hot press technology using MoSi2, Ti and B4C powders as raw materials. Effects of TiC-TiB2 particles on microstructure, mechanical properties and oxidation resistance properties of MoSi2 matrix were investigated. The results show that the flexure strength and hardness of 30%TiC-TiB2/MoSi2 composite are 468.3 MPa and 17.07 GPa, respectively. Compared with monolithic MoSi2, the flexure strength and hardness are enhanced by 63.2% and 83.5%, respectively. With the TiC-TiB2 particles content increasing, the fracture mechanism of the composites changes from intergranular fracture to transgranular fracture. The strengthening mechanisms of the composites are grain refine and dispersion strengthening. Oxidizing at 800−1 200 ℃, the mass gain of 30%TiC-TiB2 composites is almost 2.38−3.23 times as much as that of 10%TiC-TiB2/MoSi2 composites. Low melting glass phase of B2O3 can not be found in the oxidized layer, but TiO2 and SiO2 existing in the oxidation layer make TiC-TiB2/MoSi2 composites have good oxidation resistance.
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