The effects of a new type of grain growth inhibitor on vacuum sintering behavior of nanograined WC-10Co powders produced by mechanical alloying as well as its affecting mechanism were investigated. The results show that the new grain growth inhibitor can promote sintering densification process. Adding the new inhibitor to traditional transitional group element carbides, composite inhibitors become much more effective, obviously induce oriented WC grain growth and evidently encumber plate-like WC grain formation during sintering. For WC-10Co0.8VC/Cr3C2powders with 0.1% of the new additive, the density of 14.48 g/cm3can be achieved after sintering at 1 375degrees for 30 min, corresponding to the grain size of 160 nm and the micro-hardness of 2.150 GPa.

Cemented carbideis a kind of hard and brittle composite material which is different from soft metal material and hard and brittle ceramic material. Due to the different content of soft metal phase and hard phase in the material, the microstructure of the material is different, resulting in the different grinding performance of the hard alloy. The excellent physical and mechanical properties of cemented carbide contribute to the application of this kind of material in engineering, but the high hardness and high wear resistance also make it very difficult to grind it. The purpose of this project is to apply the high speed grinding technology to the processing of hard alloy, deeply study the grinding mechanism of hard alloy and the grinding mechanism of high speed grinding, and provide an effective scheme, experimental basis and theoretical basis for the solution of this difficult problem.

VC and Cr3C2 with different content of grain growth inhibitors were added to the ultrafine WC Co composite powder. The phase composition of the powder and cemented carbidewas analyzed by X-ray diffractometer. The morphology of cemented carbide was observed by SEM and TEM, and the effect of different content of grain growth inhibitors on the microstructure and mechanical properties of cemented carbide was studied. The results show that with the increase of the inhibitor of grain growth, the abnormal grain growth disappears and the grains are fine and uniform; meanwhile, it is found that the increase of VC in WC Co composite powder can rapidly improve the hardness of cemented carbide, while the appropriate amount of Cr3C2 can effectively improve the transverse fracture strength of cemented carbide.

Related link:

http://www.wococarbide.com/Library/index.html

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