TiC_(0.7)N_(0.3)增强ZrO_2基复合材料的微观结构及力学性能

为提高ZrO2基复合材料硬度,采用热压烧结法制备了TiC0.7N0.3/ZrO2复合材料,并研究了TiC0.7N0.3颗粒增强相对复合材料的物相组成、微观结构和力学性能的影响。结果表明:TiC0.7N0.3的添加具有稳定四方相ZrO2(t-ZrO2)的作用,能增加TiC0.7N0.3/ZrO2复合材料中t-ZrO2的含量,提高断裂韧性。随着热压烧结温度的升高和TiC0.7N0.3含量的增加,复合材料的硬度升高。1 400℃下热压烧结时,TiC0.7N0.3发生部分分解,分解的N与被还原的ZrO2反应生成ZrN,提高了复合材料的硬度。1 400℃下热压烧结后的35wt%TiC0.7N0.3/ZrO2复合材料的相对密度达99.9%,维氏硬度达17 GPa。而1 300℃下热压烧结后,复合材料断裂韧性较高,为6.48 MPa·m1/2。研究结果为TiC0.7N0.3/ZrO2复合材料的组织控制及性能改进提供了参考。

Microstructure and mechanical properties of TiC0.7N0.3 reinforcing ZrO2 matrix composites

To enhance the hardness of ZrO₂ matrix composites, TiC_0.7N_0.3/ZrO₂ composites were fabricated by hot pressing method, and the effects of TiC_0.7N_0.3 particle reinforcing phase on the phase composition, microstructure and mechanical properties of the composites were investigated. The results show that the addition of TiC_0.7N_0.3 has the effect to stabilize tetragonal ZrO₂ (t-ZrO₂), and can improve the t-ZrO₂ content in TiC_0.7N_0.3/ZrO₂ composites, thus improve the fracture toughness. With the hot pressing temperature and TiC_0.7N_0.3 content increasing, the hardness of composites increases. When hot pressing at 1 400 ℃, TiC_0.7N_0.3 decomposes partially, and the released N can react with reduced ZrO₂ to form ZrN, which increases the hardness of composites. The relative density of 35wt% TiC_0.7N_0.3/ZrO₂ composites after hot pressing at 1 400 ℃ exceeds 99.9% and Vickers hardness reaches 17 GPa. While the fracture toughness of composites is higher after hot pressing at 1 300 ℃, which is 6.48 MPa·m^1/2. The conclusions provide references for microstructure controlling and improvement TiC_0.7N_0.3/ZrO₂ composite properties.