热压烧结制备SiCw/ZrB2陶瓷复合材料的研究

ZrB2 Matrix Ceramic Composites by Hot-Pressed and SiC Whisker Reinforced

摘要:

在烧结温度和压力为1800 ℃和30 MPa条件下热压烧结制备ZrB2-20%(体积分数, 下同)SiCw陶瓷复合材料，并研究两种不同SiC晶须对材料的显微组织与力学性能的影响。结果表明，复合材料的弯曲强度和断裂韧性与SiC晶须的长径比有关，长径比越大材料的性能越好，弯曲强度和断裂韧性最高为651 MPa和5.97 MPa·m1/2；与单相的ZrB2材料及SiC颗粒增强ZrB2复合材料相比，断裂韧性有显著提高；其主要增韧机制为裂纹偏转、晶须桥连和拔出

Abstract:

ZrB2 based ceramic matrix composites containing two kinds of SiC whiskers were produced at 1800 ℃ under a uniaxial load of 30 MPa by hot-pressing. The microstructure and mechanical properties of the two composites were investigated. The results show that the flexural strength and fracture toughness of composites are related with the aspect ratio of SiC whisker: the larger the aspect ratio is, the better of the properties of materials. The maximum flexural strength and the fracture toughness are 651 MPa and 5.97 MPa.m1/2, respectively. The mechanical properties, especially the fracture toughness, are much higher than that of monolithic ZrB2 and SiC particles reinforced ZrB2 composites due to the main toughening mechanisms of crack deflection, whisker bridging and pullout.