烧结温度对整体PcBN材料性能的影响及作用机理

Influence of Sintering Temperature on Performance of Monolithic PcBN Material and Their Interaction Mechanism

实验采用粒度为W10的cBN微粉在国产六面顶压机上进行高压烧结,通过对样品磨耗比、显微硬度的测试与分析,获得了合成整体PcBN材料较优的烧结工艺参数:烧结压力为5.4GPa,烧结温度为1500℃,烧结时间为240s,其显微硬度为HV3897、磨耗比为8750;结合SEM、TEM、EDS、XRD对整体PcBN烧结样品的微观形貌、元素分布及物相组成进行分析。结果表明,整体PcBN材料高压烧结聚结机理为cBN颗粒的高压破碎及塑性变形,是cBN-cBN直接结合和cBN颗粒表面与粘结相的冶金反应形成的cBN-M-cBN中介结合,同时得出粘结剂反应生成了固结性能良好的AlN和硬度与韧性较高的AlB_2,提高了粘结相的硬度和韧性。

In the experiment, cBN powder of W10 particle size is used for high pressure sintering by domestic cubic press. Optimized sintering process parameter for monolithic PcBN material synthesis has been obtained through test and analysis of wear ratio and microhardness of the samples： when sintering pressure is 5.4GPa, sintering temperature is1500℃ and sintering time is 240 s, its microhardness and wear ratio are HV3897 and 8750 respectively; the micro morphology, element distribution and phase composition of the monolithic PcBN sintered samples have been analyzed by SEM, TEM, EDS and XRD.Result shows that the high pressure sintering coalescence mechanism of monolithic PcBN materials is high pressure crushing and plastic deformation of cBN particles, and cBN-McBN intermediary combination has been formed through cBN-cBN direct bonding and through metallurgical reaction of the surface and bonding phase of cBN particles. Meanwhile, bond reaction generates AIN with good consolidation properties and A1B2 with higher hardness and toughness, which promotes the hardness and toughness of the binding phase.