高温高压对PDC硬质合金基体微观结构与性能的影响

Effects of high temperature and high pressure on microstructure and properties of cemented carbide substrate of PDC

采用金相显微镜、SEM、XRD和EDX对合成PDC所用的硬质合金基体在高温高压前后的微观结构和物相进行了分析比较,并对其硬度、密度、矫顽磁力、钴磁和抗弯强度(TRS)分别做了测定,结果表明:(1)经过高温高压后,硬质合金基体中的粗晶WC有轻微的细化;(2)在合成PDC的温度、压力和时间条件下,硬质合金基体的物相没有发生明显变化;(3)高温高压后基体界面附近的钴含量显著降低,但离界面3mm以上区域的钴含量趋于正常;(4)高温高压后硬质合金基体的硬度和密度增加,抗弯强度下降,钴相分布的均匀性变差。

The cemented carbide substrates used for preparing PDC were analyzed by optical microscope,XRD,SEM and EDX before and after being treated at high temperature and high pressure（HT/HP） respectively.Their hardness,density,coercivity,the content of the cobalt and transverse rupture strength（TRS） were also measured.The results show that：（1） After HT/HP treatment,the coarse-grained WC particles in the cemented carbide are refined slightly.（2） The phases in the cemented carbide haven＇t changed under the condition of the PDC preparation.（3） The content of the cobalt in the substrate is lowered significantly near the interface after HT/HP,but it stays normal 3mm away from the interface.（4） The hardness and density of the cemented carbide substrate increases after HT/HP,but the TRS of the substrate decreases and the distribution of the cobalt phase in the cemented carbide becomes uneven.