碳纳米管添加量对Ti(C,N)基金属陶瓷组织和力学性能的影响

摘要

采用真空烧结工艺制备了Ti(C, N)基金属陶瓷,通过XRD、TEM和SEM等手段研究碳纳米管(CNTs)对金属陶瓷组织和性能的影响.结果表明:与未加碳纳米管的基体组织相比,添加CNTs的金属陶瓷组织中具有"白芯-灰壳"结构的小颗粒大大增加,金属陶瓷晶粒逐渐细化且分布均匀;当CNTs添加量(质量分数)为0.5%时,Ti(C, N)基金属陶瓷的硬度可达90.9HRA;金属陶瓷的抗弯强度比未加碳纳米管的试样提高14.1%,可达2 180.7 MPa,其强化机制主要为细晶强化;金属陶瓷的断裂韧性比未加碳纳米管的试样提高18.5%,可达14.7 MPa·m1/2,CNTs对金属陶瓷强韧化机制主要为桥联作用、拔出效应和裂纹偏转作用.%Ti(C, N)-based cermets with CNTs addition were produced by vacuum sintering. The effects of carbon nanotubes (CNTs) addition on the microstructure and mechanical properties of Ti(C, N)-based cermets were studied by X-ray diffractometry (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that, compared with the base microstructure of cermets without CNTs addition, the grains of the cermets with CNTs addition are refined gradually and distributed homogeneously, and the amount of "white core-gray rim"increases. When the CNTs addition (mass fraction) is 0.5％, the hardness of the cermets is up to 90.9HRA, the transverse rupture strength (TRS) of the cermets is 2 180.7 MPa, which is about 14.1％ higher than that of the cermets without CNTs addition, and the reinforcement mechanism of the cermets is caused by frae-grain strengthening. The fracture toughness (KIC) of the cermets with 0.5％ CNTs addition is 14.7 MPa·m1/2, which is about 18.5％ higher than that of the cermets without CNTs addition. The toughening mechanism of the cermets with CNTs addition is caused by crack bridging, pull-out mechanism and crack deflection.