以氧化铝陶瓷为研究对象介绍了CO2激光热应力切割脆性材料的机理。采用Ansys的APDL编程语言, 建立三维对称的氧化铝陶瓷基片热应力切割有限元仿真模型, 研究了切割过程中的温度场和热应力场的分布, 实现裂纹尖端的扩展速度的动态仿真。研究发现激光切割路径上节点的正应力σy经历“无应力拉应力压应力拉应力无应力”的变化过程, 直至裂纹扩展; 激光功率与温度场最高温度成正比, 功率增大情况下断裂时产生的拉应力σy加大, 裂纹萌生早, 且断裂表面的微裂纹加大。最后, 采用对比实验验证了分析结果。

Taking example for alumina ceramic, this paper briefly introduces the mechanism of CO2 laser-controlled thermal stress cutting of brittle materials. In order to study the distributions of temperature field and thermal stress field, a three-dimensional axial symmetric model of alumina ceramic is established by using APDL programming language of Ansys software. The normal stress σy of nodes which are in the laser scanning path, is in the process of "no stress-tensile stress-compressive stress-tensile stress-no stress" during cutting process, until the crack grows. The study reveals that laser power and the maximum temperature is directly proportional during the cutting process. While the laser power increases, the crack initiates earlier and the microcrack of the fracture surface becomes bigger with greater tensile stress. The results are proved by comparative experiments.