空间参数对毫秒–纳秒组合激光烧蚀铝合金的影响

Effect of Spatial Parameters on Combined Millisecond-Nanosecond Laser Ablation of Aluminium Alloys

摘要: 烧蚀形貌反映了激光加工的质量。因此，研究组合激光在加工时的温度及形貌十分重要。本文主要研究了空间参数(光斑大小及组合方式)对铝合金烧蚀形貌及温度的影响。实验结果表明，在毫秒激光作用后，铝合金表面温度逐渐升高到1800 K左右出现平台期。在纳秒激光作用后，铝合金表面温度瞬间升高到3200 K左右并快速下降，纳秒激光的作用有助于熔融物的迁移。当纳秒光斑大时，烧蚀形貌呈碗状，深径比较小，边缘基本没有喷溅物。当纳秒光斑较小时，烧蚀形貌接近于孔状，深径比较大，边缘喷溅物较多。通过对物理模型的分析和仿真，探讨了空间参数对熔池影响的物理机制。本文的研究成果对激光加工效果的控制有重要的指导意义。

Abstract: The morphology of ablation is indicative of the quality of laser processing. Therefore, it is crucial to examine the temperature and morphology of combined laser processing. This paper investigates the impact of spatial parameters, such as spot size and combination mode, on the ablation morphology and temperature of aluminium alloy. The experimental results indicate that following millisecond laser action, the surface temperature of the aluminium alloy gradually increases to approximately 1800 K, and a plateau period ensues. Following nanosecond laser action, the surface temperature of the aluminium alloy instantaneously increases to approximately 3200 K, before decreasing rapidly. The nanosecond laser action facilitates the migration of the melt. When the nanosecond spot is large, the ablation pattern takes on a bowl shape, with a relatively small depth-to-diameter ratio and no spatter at the edge. Conversely, when the nanosecond spot is small, the ablation pattern is more hole-like, with a relatively large depth-to-diameter ratio and more spatter at the edge. The influence of spatial parameters on the molten pool is explored through the analysis and simulation of the physical model. The research findings in this paper are significant for guiding the control of laser processing effects.