Molecular dynamics study on grinding mechanism of polycrystalline silicon carbide

MH Chen and HF Dai, DIAMOND AND RELATED MATERIALS, 130, 109541 (2022).

DOI: 10.1016/j.diamond.2022.109541

In this paper, stress, temperature, dislocation, surface morphology and crystal structure of polycrystalline silicon carbide under different grinding speeds and grain sizes are studied by molecular dynamics simulation. Influence of silicon carbide with different grain sizes on formation and emission of dislocations and relationship between formation and emission of dislocations under different grinding speeds are revealed. By comparing number of amorphous atoms and generation of dislocations between monocrystalline silicon carbide and polycrystalline silicon carbide at different grinding speeds, it is observed that thickness of subsurface damage layer of monocrystalline silicon carbide correspondingly increases with grinding speed. In contrast, damage layer of polycrystalline silicon carbide is determined by the joint action of grain size and grinding speed, and it does not decrease with increase in grinding speed, unlike monocrystalline silicon carbide. Accumulation of dislocations at the grain boundary causes strengthening between the grain boundaries, and alters the cutting force. In the grinding process, although grinding speed is not the primary factor affecting surface topography, it is the main factor affecting workpiece temperature.

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