Nano-cemented Carbide and Traditional Carbide Comparison

Due to nano-cemented carbide improves the contradictions between the hardness and the toughness which has a remarkable increase in mechanical properties compared with common tungsten carbide. There are two aspects of comparisons between nano-cemented carbide and traditional carbide as follow:

1. Porosity defects

Based on the theory and experience in machining, with the decreasing granularity, the porosity defects decrease and the fracture toughness enhances. Thus, the porosity defects of nano-cemented carbide are lower than traditional tungsten carbide. When the granularity less than 30nm, the granularity of porosity defect will be smaller and the fracture toughness will be remarkably improved.

2. Interface

Compared with traditional carbide, nano-cemented carbide has more interfaces, Crack paths through the hard phase WC interface and Co binder phase interface. In other words, Crack through grain boundaries in nano crystalline increased massively this material, which is indicative of the crack is not a priority but is to advance along the interface by bonding, forming a dense shallow dimple in cemented carbide material. In bond by B / C interface with a lot of broken plastic deformation presence, enhanced by the crack path B / C interface percentage will significantly improve the ability to process fracture, thereby enhancing the overall toughness of nano-carbide materials.

In addition, viewed from the interfacial effect related deformation mechanism, when the grain size to the nanometer level, migration and dislocation motion grains have become relatively difficult, instead of sliding and the proliferation of small-scale grain boundaries, such as changes in grain shape, grain rotation. WC particles covered by nano Co, when the nano crystalline Co called the control phase, corresponding to the mechanical properties of the cemented carbide has occurred. It should be noted that the nano cemented carbide wear than conventional carbide, but it does not follow the traditional mechanism that the wear resistance of tungsten carbide particles increases with the decreasing the granularity.

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