Laser-assisted water jet machining of high quality micro-trap structures on stainless steel surfaces  

不锈钢表面高质量微陷阱结构的激光辅助水射流加工

作　　者：LIU Li YAO Peng CHU Dong-kai XU Xiang-yue QU Shuo-shuo HUANG Chuan-zhen 刘莉;姚鹏;褚东凯;徐相悦;屈硕硕;黄传真(山东大学机械工程学院先进射流工程技术研究中心,山东济南250061;山东大学高效洁净机械制造教育部重点实验室,山东济南250061;燕山大学机械工程学院,河北秦皇岛066004)

机构地区：[1]Center for Advanced Jet Engineering Technologies(CaJET),School of Mechanical Engineering,Shandong University,Jinan 250061,China [2]Key Laboratory of High Efficiency and Clean Mechanical Manufacture,Ministry of Education,Shandong University,Jinan 250061,China [3]School of Mechanical Engineering,Yanshan University,Qinhuangdao 066004,China

出　　处：《中国光学（中英文）》2024年第6期1476-1488,共13页Chinese Optics

基　　金：国家自然科学基金(No.52075302);深圳市科技计划(No.GJHZ20210705142537003)。

摘　　要：Secondary electron emission(SEE)has emerged as a critical issue in next-generation accelerators.Mitigating SEE on metal surfaces is crucial for enhancing the stability and emittance of particle accelerators while extending their lifespan.This paper explores the application of laser-assisted water jet technology in constructing high-quality micro-trap structures on 316L stainless steel,a key material in accelerator manufacturing.The study systematically analyzes the impact of various parameters such as laser repetition frequency,pulse duration,average power,water jet pressure,repeat times,nozzle offset,focal position,offset distance between grooves,and processing speed on the surface morphology of stainless steel.The findings reveal that micro-groove depth increases with higher laser power but decreases with increasing water jet pressure and processing speed.Interestingly,repeat times have minimal effect on depth.On the other hand,micro-groove width increases with higher laser power and repeat times but decreases with processing speed.By optimizing these parameters,the researchers achieved high-quality pound sign-shaped trap structure with consistent dimensions.We tested the secondary electron emission coefficient of the"well"structure.The coefficient is reduced by 0.5 at most compared to before processing,effectively suppressing secondary electron emission.These results offer indispensable insights for the fabrication of micro-trap structures on material surfaces.Laser-assisted water jet technology demonstrates considerable potential in mitigating SEE on metal surfaces.金属表面二次电子发射的抑制对于提高粒子加速器的稳定性、发射度及寿命具有十分重要的作用,已成为新一代加速器面临的最为关键的问题。本文采用激光辅助水射流技术在粒子加速器组成的重要材料316L不锈钢表面开展了高质量微陷阱结构的加工研究。系统分析了激光重复频率、脉冲宽度、平均功率、射流压力、重复次数、水射流偏置距离、焦平面位置、槽间偏置距离和加工速度对316L不锈钢表面形貌、槽深、槽宽和“井”字陷阱结构形貌的影响规律。研究结果表明:微槽深度随激光功率增加而增大,随射流压力增加而减小,随加工速度增加而减小,受重复次数影响较小;槽宽随激光功率增加而增大,随加工速度增加而减小,随重复次数增加而增大。通过参数优化,可以加工得到尺寸规整且表面质量较高的“井”字陷阱结构。本研究测试了“井”字结构的二次电子发射系数,较加工前最大降低了0.5,有效抑制了二次电子发射。本研究结果对于构建材料表面微陷阱结构具有非常重要的应用参考,激光辅助水射流加工技术有望应用于金属表面二次电子抑制加工。

关 键 词：laser-assisted water jet 316L stainless steel micro-trap structures "well"structure surface morphology secondary electron emission(SEE) groove depth groove width 

分 类 号：TN249[电子电信—物理电子学]