TiC-TiB_2复合陶瓷磨削裂纹的试验研究

Study on the crack propagation during the grinding of TiC-TiB_2 composite ceramics

本文基于压痕断裂力学,分析了TiC-TiB2复合陶瓷磨削裂纹的特征,并对TiC-TiB2复合陶瓷磨削裂纹的形成及扩展过程进行了研究。磨削实验发现:TiC-TiB2陶瓷磨削裂纹密度较大,为穿晶裂纹和沿晶裂纹的混合形式;裂纹易在陶瓷内部缺陷处形成,并因陶瓷显微组织不均匀性而发生钉扎、偏转、分叉及桥接,使得材料中裂纹的扩展呈现不连续性;TiB2硬质相会对裂纹的扩展有一定的阻碍作用。

Based on the indentation fracture mechanics,the characteristics of grinding cracks in TiC-TiB2 composite ceramics grinding was analyzed,meanwhile,the formation and propagation of grinding cracks during TiC-TiB2 composite ceramics gringding were also studied.It was found that the grinding cracks density of TiC-TiB2 was high in a hybrid form of transcrystalline cracking and intercrystalline cracking;the cracks were formed commomly around the defects of ceramics,and phenomena such as pinning,deflection,branching and bridging of cracks were induced due to microstructure heterogeneity of the ceramics,which led to crack propagating discontinuously;the crack propagation was impeded by the hard phase TiB2 existed in the ceramics.