热压烧结制备Al2O3/TiCN-Ni-Ti陶瓷复合材料的组织与性能

采用真空热压烧结方法制备Al2O3/Ti(C,N)-Ni-Ti陶瓷基复合材料,采用X射线衍射与扫描电镜分析材料的物相组成和显微结构,研究烧结工艺对材料物相组成、显微结构和力学性能的影响。结果表明:Ni和Ti的添加显著提高复合材料的强度和韧性;温度小于1 600℃时,复合材料的力学性能随热压温度的升高而升高;温度高于1 600℃时,温度升高及保温时间延长不仅会导致Al2O3晶粒的异常长大和Ti(C,N)的分解,而且会使Ni发生聚集现象,复合材料的力学性能下降;当烧结温度为1 600℃、保温时间为30 min时,制备的Al2O3/Ti(C,N)-Ni-Ti陶瓷复合材料的力学性能最佳,其相对密度达到99.4%,抗弯强度为820 MPa,断裂韧性达到9.3 MPa.m1/2。

Microstructures and properties of Al2O3/TiCN-Ni-Ti composites fabricated by hot pressing

Al2O3/Ti(C,N)-Ni-Ti composites were fabricated by vacuum hot pressing.The microstructures of the materials were characterized by XRD and SEM,and the effects of sintering temperature and holding time on the phase components,microstructure and mechanical properties were investigated.The results indicate that the addition of Ni and Ti can significantly increase the strength and toughness of the composites.The mechanical properties of the composites improve with increasing hot pressing temperature while the temperature is lower than 1 600 ℃.When the hot pressing temperature is above 1 600 ℃,the increase of temperature or excess extension of holding time will not only lead to the overgrowth of Al2O3 grains and the decomposition of Ti(C,N),but also promote the aggregation of the melted metallic Ni,which is detrimental to the mechanical properties.The Al2O3/Ti(C,N)-Ni-Ti composite sample sintered at 1 600 ℃ for 30 min achieves a relative density of 99.4%,a bending strength of 820 MPa and a fracture toughness of 9.3 MPa?m1/2.