氮含量对Ti(C,N)基金属陶瓷显微组织与磨粒磨损行为的影响

采用真空烧结方法制备了4种氮含量的Ti(C,N)基金属陶瓷,测试了试样的抗弯强度、硬度、断裂韧性等力学性能,用扫描电镜、能谱仪等研究了N含量对其显微组织及磨粒磨损行为的影响。结果表明:在一定范围内随N含量的增加,硬质相芯部逐渐细化且分布均匀,环形相厚度变薄、体积分数减小;磨粒磨损形貌中犁沟所占的比例减少,微观脆性断裂形成的凹坑增加,耐磨粒磨损性能逐渐提高。随N含量增加,Ti(C,N)基金属陶瓷的抗弯强度呈现出先增加后减小的趋势,断裂韧度逐渐递减,硬度变化不大。当N含量为3.6%时(文中含量均为质量分数),Ti(C,N)基金属陶瓷综合力学性能最佳,其抗弯强度为1 873 MPa,硬度为89.9 HRA,断裂韧度为20.7 MPa.m1/2。

Effect of Nitrogen Addition on Microstructure and Abrasive Wear Behavior of Ti（C,N）-based Cermets

A series of Ti（C,N）-based cermets with high nitrogen addition were produced by vacuum sintering technolo- gy. The mechanical properties of TRS, HRA and Kxc had been tested. The effects of N addition on the microstructure and abrasive wear behavior of Ti（C,N）-based cermets had been studied by SEM, EDX, etc. The results show that the hard phase core becomes finer gradually and distributes evenly with the increase of nitrogen addition, and the rim phase becomes thinner and the volume fraction decreases obviously. At the same time, the cermets exhibit higher abrasive wear resistance as the N addition increases, and the abrasive wear morphology of the cermets changes from deep grooves formed by plastic deformation to small pits caused by micro brittle fracture. With the increase of nitrogen addition, the TRS of the Ti（C,N）- based cermets increases firstly and then decreases, the K~c decreases gradually, but the HRA shows little change. When the amount of N addition is 3.6% （mass fraction）, the cermets have the best properties with TRS of 1 873 MPa, hardness of 89.9 HRA and Kic of 20.7 MPa. m^1/2.