引入MgAl2O4对Ti3SiC2基复合材料性能的影响

Effect of addition of MgAl2O4 on properties of Ti3SiC2 matrix composites

  • 摘要: 采用反应热压烧结法制备MgAl2O4/Ti3SiC2复合材料, 研究热压温度和MgAl2O4含量对该复合材料相组成、力学性能及抗氧化性能的影响。结果表明:热压温度影响MgAl2O4/Ti3SiC2复合材料相组成, 在1 450 ℃烧结可得到性能良好的MgAl2O4/Ti3SiC2复合材料。引入适量的MgAl2O4, 起到弥散强化的作用, 有助于提高复合材料的力学性能, 当引入量为20wt%时, 抗弯强度为527.6 MPa, 断裂韧性为7.09 MPa·m1/2。MgAl2O4/Ti3SiC2试样的抗氧化性能优于Ti3SiC2试样。MgAl2O4/Ti3SiC2复合材料在1 400 ℃氧化后的氧化层分两层, 外层是Mg0.6Al0.8Ti1.6O5和金红石型TiO2, 内层是由TiO2、方石英SiO2及少量未氧化的基体相混合组成。

     

    Abstract: Ti3SiC2/MgAl2O4 composites were fabricated by reactive hot pressing method. The effects of the content of MgAl2O4 and hot pressing temperature on the phase constituent, mechanical properties and oxidation resistance of composites were investigated.The results show that hot pressing temperature affects the phase composition of Ti3SiC2/MgAl2O4 composites and it can get good properties of Ti3SiC2/MgAl2O4 composite materials in 1 450 ℃. MgAl2O4 by introducing the appropriate content has the effect of dispersion strengthening and contributes to improving the mechanical properties of composite materials. When the addition amount is 20wt%, bending strength is 527.6 MPa and fracture toughness is 7.09 MPa·m1/2. The oxidation resistance of Ti3SiC2/MgAl2O4 sample is better than pure Ti3SiC2. The oxidation layers of Ti3SiC2/MgAl2O4 composites are composed of two layer at 1 400 ℃, the outer consists of Mg0.6Al0.8Ti1.6O5 solid solution and rutile of TiO2, and the inner is a mixture of TiO2, cristobalite and a small amount of unoxidized matrix.

     

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