Crack Initiation Analysis of Si3N4 Bearing Based on Molecular Dynamics

The issue of high strength and low toughness in Si3N4 bearings has been identified as a significant challenge. Overload conditions can result in the formation of fatigue cracks at the subsurface level, ultimately leading to bearing failure. The experimental model of Si3N4 friction is constructed using molecular dynamics, and the process of crack generation in Si3N4 bearings is subjected to detailed microscopic analysis. The Si3N4 deep learning potential is established through first-principle calculations and DP-GEN training, which describes the interaction mode and energy between molecules. This paper examines the friction force and temperature, defect process, and crack initiation during the friction process, and provides a detailed investigation of the crack initiation mechanism of Si3N4 bearings. As the friction distance increases, the total friction force rises. The impact on the atomic volume of the collar, both in front and on either side, results in a reduction in the volume of the crystal. This leads to the formation of defects in the crystal structure, which in turn causes the formation of cracks in the collar. Analyzing the crack formation process in Si3N4 bearings provides insights that can be used to enhance the durability of bearings.