脉冲激光精微烧蚀合金钢表面热影响研究

Thermal Effect Study on Alloy Steel Surface Precision Ablation by a Pulsed Laser

基于脉冲累积效应对纳秒激光精微烧蚀18Cr2Ni4WA钢进行传热分析,并在MATLAB中进行温度场仿真;采用波长为532 nm、脉宽为8 ns的纳秒脉冲激光对18Cr2Ni4WA钢进行烧蚀实验,分析了脉冲累积下热传导过程;采用单元素法分析激光能量密度、脉冲数对靶材表面几何形貌的影响规律,并将靶材表面损伤区域分为激光烧蚀区域和热影响区域。实验结果表明:烧蚀凹坑半径随脉冲数的增加而增大,但半径的增大不是持续的;在激光单脉冲能量40 mJ、10个脉冲数下,靶材表面的机械划痕因质量流动而去除,达到相对平整的形貌。本文对探索合金钢烧蚀特性有参考意义。

In consideration of the pulse accumulation effect, process of heat transfer of 18 Cr2 Ni4 WA steel ablated by nanosecond laser was analyzed and the temperature distribution was simulated with MATLAB code.The ablation experiments of 18 Cr2 Ni4 WA steel were carried out with a nanosecond laser operated at the wavelenth of 532 nm and the pulse duration 8 ns, the single factor method is used to analyze the influence of laser energy density and pulse number on the surface geometry of the target material, and the surface damage area of the target material is divided into laser ablation area and heat-affected area.The experimental results show that the radius of the ablation pit increases with the increase of the pulse number, but this increase is not continuous.Under the laser pulse energy of 40 mJ and the pulse number of 10,mechanical scratches on the surface of the target are removed by mass flow, achieving a relatively flat topography.