Study Of The Interface Between Structure And Properties. The Pcd Layer And The Wc-co Substrates

The quality of PDC, used as cutting parts for PDC bits, dicidedly influences the drilling effect. PDC is super-hard composed of manu-diamond with a little binders and hard alloys and it is processed by the method of HPHT. During the course of sintering, the thermal expansion coefficient and elastic ratio have great difference between the layer of PDC and the hard alloys. The great difference would induce the great residual stress at the interface easily when cooled, decreasing PDC's intensity. So the layer of PDC would pull out easily and the bit is off. Therefore, to study interfacial structure of two-phase of PDC, to improve the interfacial combination of two-phase of PDC and to increase the anti-impact and the thermal stability of PDC has been a important subjects in the field of super-hard materials.In the guidance of my tutor and on the base of the predecessor's studying, five kinds of special interfacial structure of PDC had been studied through the methods of wear property, anti-impact, thermal stability,supersonic nondestructive evaluation(C scan ) and SEM analysis in this paper.It shows that in the same technological conditions:1 ,The interfacial structure of the PDC layer and WC-Co substrate has little influence on the wear property. The diamond and grains can sinter better, causing the excellent wear property of PDC.2, The interfacial structure of the PDC layer and WC-Co substrate has great influence on the anti-impact property. The anti-impact property of PDC increased massively from flat, V vessel, U vessel, ring vessel to ring claw-tooth on the tooth shape of WC-Co substrate.3, The temperature influenced the wear property and the anti-impact property of PDC obviously, and it has greate influence on the anti-impact property. The thermal stability of the vessel-shaped interface structure is better than the flat interface.4,Changing the interfacial structure can decrease the influence of residual stress on PDC layer and can improve its durability effectly. But the groove or saw-tooth parts...