关键词: 氧化镓晶体, 径向裂纹成核, 裂纹扩展, 刻划试验, 应力分析

Abstract: In order to analyze the crack nucleation position and propagation direction of the new-generation optoelectronic material gallium oxide crystal during ultra-precision grinding and lapping processes, a model of elastic stress field of gallium oxide(010) crystal plane was established by single abrasive grain, and the critical cutting depth of the brittle-plastic transition of gallium oxide(010) crystal plane was analyzed. The nucleation position and propagation direction of radial cracks on the surfaces were predicted during the scribing processes of gallium oxide crystals by MATLAB analysis. The analysis results show that when the cutting depth is less than the critical cutting depth, the radial crack nucleation position is behind the abrasive grain, and the angle between the crack propagation direction and the cutting direction is about 33°. When the cutting depth exceeds the critical cutting depth, the radial crack nucleation position further moves behind the abrasive grain, and the angle between the crack generation direction and the scoring direction is about 51°. In order to verify the theoretical analysis results, a nano-scoring test on gallium oxide crystals was performed. Comparative analysis show that the analytical results of the gallium oxide stress field are highly consistent with the experimental data. Under linear loading conditions, the radial crack deflection angle of the Cube diamond indenter on the gallium oxide crystal(010) crystal plane is between 33.37°and 51.45°.

Key words: gallium oxide crystal, radial crack nucleation, crack propagation, scribing test, stress analysis