磁场辅助的皮秒激光诱导液体等离子体表面微织构加工技术及其机理研究

Picosecond laser direct writing is one of the most important technologies to create micro surface textures, however, it still suffers from some limitations in energy utilization, machining efficiency and multi-materials machining capability. This proposal aims to create complex micro-features on the surface of multi-materials using picosecond laser induced liquid plasma micromachining technology, and magnetic field is incorporated to improve the machining accuracy, stability and efficiency.. Firstly, the mechanism of single-pulse laser induced plasma micromachining is studied to model the micro-plasma initiation, its subsequent spatial and temporal evolution as well as its interaction with the workpiece material. Then an electromagnetic field is designed by FEM to study the effect of magnetic field on the induced plasma confinement and the surface morphology. Furthermore, the hybrid mechanism of magnetic field assisted laser induced liquid plasma surface texturing is explored and a model of multi-pulses laser induced plasma micromachining is developed. Finally, the machining strategy of creating complex micro-features on multi-materials is obtained by the integration of the model of laser induced plasma micromachining on multi-materials and the path planning. The findings of this research will promote the industrial applications by use of picosecond laser surface texturing.

皮秒激光直写是材料表面功能微织构加工的重要实现技术，但在多材料加工、能量利用率及加工效率方面存在局限性。本项目主要针对为解决皮秒激光微织构加工局限性问题开发的新工艺技术—激光诱导液体等离子体微加工技术展开研究，融合磁场辅助复合机制，以提升多材料表面复杂形状微织构的加工精度、稳定性及效率为目标，分别研究皮秒激光诱导液体等离子体单脉冲微加工机理，建立金属表面加工物理模型；利用有限元辅助设计电磁场，建立磁场对单脉冲下等离子体压缩及工件表面微坑形貌的影响规律；探索磁场作用与皮秒激光诱导液体等离子体微加工复合机制，揭示磁场辅助下激光诱导液体等离子体微织构加工机理，建立连续脉冲加工模型；替换加工材料建立多材料表面微织构加工模型，优选工艺参数，结合路径规划获取复杂形状微织构加工控制策略。项目的研究成果对于促进皮秒激光微织构加工的工程应用，具有重要的理论意义和应用价值。

本项目重点针对皮秒激光表面微织构加工在多材料加工、能量利用率及加工效率方面存在的局限性问题，开发皮秒激光诱导液体等离子体微加工技术，以提升多材料表面微织构加工精度、质量及效率为目标，对比分析了皮秒激光直写微加工和皮秒激光诱导液体等离子体微加工效果，确立了皮秒激光诱导液体等离子体微加工的优势，进一步建立了皮秒激光诱导液体等离子体单脉冲物理模型，揭示了微加工机理；提出了磁场辅助皮秒激光诱导液体等离子体微加工技术，揭示了工艺参数对等离子体、空泡及微加工的影响规律/机理；提出了流动水辅助皮秒激光诱导液体等离子体微加工技术，研究了工艺参数对微加工结果影响规律，并进行了工艺参数优化；采用优化的工艺参数实现了不锈钢、陶瓷、玻璃、PMMA等材料表面不同微结构的高质量加工。项目研究提供了更优的皮秒激光表面微织构加工技术，可提升微织构加工精度、加工质量及加工效率，拓展其在关键工程元器件中的应用潜力，具有重要的应用前景和战略经济价值。