单颗磨粒刻划氧化镓晶体表面的裂纹成核位置及扩展方向研究

Crack Nucleation Position and Propagation Direction of Single Abrasive Grain Scribing Gallium Oxide Crystal Surfaces

为了分析新一代光电子材料氧化镓晶体在超精密磨削、研磨加工过程中的裂纹成核位置及扩展方向,建立了单颗磨粒刻划氧化镓(010)晶面的弹性应力场模型,分析了氧化镓(010)晶面的脆塑性转变临界切削深度。通过MATLAB软件分析预测刻划氧化镓晶体过程中表面径向裂纹的成核位置及扩展方向,分析结果表明:当切削深度小于临界切削深度时,径向裂纹成核位置在磨粒的后方,裂纹扩展方向与切削方向之间的夹角在33°左右;当切削深度超过临界切削深度时,径向裂纹成核位置进一步向磨粒后方移动,裂纹生成方向与刻划方向之间的夹角在51°左右。为验证理论分析结果,对氧化镓晶体进行了纳米刻划试验,对比分析表明,氧化镓应力场的解析结果与试验数据高度一致。在线性加载条件下,Cube金刚石压头在氧化镓晶体(010)晶面上产生的径向裂纹偏转角在33.37°~51.45°之间。

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°.