不同TiN含量整体式PCBN复合材料微观组织及性能研究

在高温高压烧结条件下以TiN为主要结合剂，加入一定量的Al，研究TiN含量对整体聚晶立方氮化硼(PCBN)复合材料微观组织与力学性能的影响。分别对烧结样品进行物相组成分析、微观结构观测以及体积密度和硬度测试。结果表明:CBN与结合剂TiN、Al反应生成TiB₂、AlN，TiN与Al发生反应生成Al₃Ti ，TiN与反应生成物AlN、TiB₂、Al₃Ti等构成黏结相均匀分布于 CBN晶界周围，牢固地将CBN 晶粒黏结在一起，有效地提高了整体PCBN复合材料的结合强度。低含量TiN对整体PCBN的致密度和硬度均有一定程度的提升，在TiN、Al、CBN的质量分数分别为10%、10%、80%时，整体PCBN复合材料的力学性能达到最佳。 

Microstructure and properties of solid PCBN composites with different TiN contents

The solid polycrystalline cubic boron nitride (PCBN) was sintered by CBN powders, TiN and a certain amount of Al. It was investigated that the effect of TiN contents on the microstructure and mechanical properties of the solid PCBN composites under high pressure and high temperature. The phase composition analysis, microstructure observation, density and hardness test of the sintered samples were carried out. The results show that CBN reacts with the binders of TiN and Al to form TiB₂ and AlN. TiN reacts with Al to form Al₃Ti, TiN and AlN. The TiN, AlN, TiB₂ and Al₃Ti are uniformly distributed around the CBN grain boundary and the grains are firmly bonded together, which effectively improves the bonding strength of PCBN composite. The lower content of TiN has a certain increase in the density and hardness of the solid PCBN. When the mass fractions of TiN, Al and CBN are 10%, 10% and 80%, respectively, the solid PCBN composites has the best mechanical properties.