烧结温度对高含量聚晶立方氮化硼组织与性能的影响

Effect of Sintering Temperature on Microstructure and Performance of High Content Polycrystal Cubic Boron Nitride

以立方氮化硼粉、钛粉、铝粉为原料,在高温(1400~1600℃)和超高压(6.5 GPa)条件下采用原位合成方法制备高含量聚晶立方氮化硼(PcBN),研究了烧结温度对PcBN力学性能、微观结构和切削性能的影响。结果表明:制备得到的PcBN均主要由BN、TiN、TiB_(2)、AlN等物相组成;随着烧结温度的升高,PcBN内部孔隙数量减少,密度增大,显微硬度和抗弯强度先升高后降低,PcBN刀具在切削行程长度达10 km后的后刀面磨损量先减小后增大。当烧结温度为1550℃时,PcBN的综合性能最佳,其抗弯强度和显微硬度最大,分别为969 MPa,40.7 GPa,后刀面磨损量最小,为0.26μm。

By taking cubic boron nitride powder,titanium powder and aluminum powder as raw materials,high content polycrystal cubic boron nitride(PcBN)was prepared by in-situ synthesis method at high temperatures(1400-1600℃)and an ultra-high pressure(6.5 GPa).The effects of sintering temperature on the mechanical properties,microstructure and cutting property of PcBN were investigated.The results show that the prepared PcBN all consisted of BN,TiN,TiB_(2) and AlN phases.With the increase of sintering temperature,the number of pores in PcBN decreased,the density increased,the microhardness and flexural strength increased first and then decreased,and the flank wear loss of PcBN tool for cutting run length of 10 km decreased first and then increased.At the sintering temperature of 1550℃,PcBN had the best comprehensive properties with the largest flexural strength of 969 MPa,the largest microhardness of 40.7 GPa,and the smallest flank wear loss of 0.26μm.