Nano-cemented Carbide Description

How to balance the wear resistance and the toughness is the important direction of tungsten carbide research. Some new related studies show that when the content of tungsten carbide binder phase remain unchanged, the granularity of tungsten carbide (WC) hard phase decreases to less than 0.8μm, the hardness and toughness have been remarkably improved. And with the decreasing granularity, the effect will be more obvious. Therefore, nano-cemented carbide is becoming a hot spot in the study of tungsten carbide gradually. At present, the general nano-cemented carbide refers to the tungsten carbide less than 250nm, and tungsten carbide with granularity under 30nm is in the stage of research and development, which does not make a further promotion for using.

Nano-cemented carbide gives a new way to deal with the contradictions between the hardness and the strength of tungsten carbide. It has both of high hardness and high strength, which has an advantage in machining some hard and brittle materials compared with tungsten carbide with common structure. For instance, the hardness of nano-cemented carbide WC-Co reaches HRA93, and the transverse breaking strength can be higher than 5000MPa, which greatly satisfies the requirements of modern industries and special material field, especially for tools and mould machining with high loading, high stress, such as PCB (Printed Circuit Board) micro drills or end mills, monolithic cemented carbide drill and some products in high-end fields.

However, there are some problems remain in nano-cemented carbide. Generally, the finer granularity of traditional tungsten carbide, the hardness will increase and the breaking strength will decrease. This is so that when the grain is reduced to a certain extent, such as when the nanometer size, whether the fracture toughness decreased a lot, current research, there are still some uncertainties. Studies have shown that when the carbide grain refinement to the nano scale, its mechanical behavior and performance will have unpredictable change.

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