• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2019, Vol. 55 ›› Issue (9): 198-205.doi: 10.3901/JME.2019.09.198

• 制造工艺与装备 • 上一篇    下一篇

纳米孪晶立方氮化硼的飞秒激光材料去除机理

靳田野1, 陈俊云2, 王金虎1, 赵清亮1   

  1. 1. 哈尔滨工业大学精密工程研究所 哈尔滨 150001;
    2. 燕山大学车辆与能源学院 秦皇岛 066004
  • 收稿日期:2018-04-19 修回日期:2018-10-16 出版日期:2019-05-05 发布日期:2019-05-05
  • 通讯作者: 陈俊云(通信作者),女,1983年出生,副教授,硕士研究生导师,主要研究方向为新型纳米孪晶材料刀具研制和高精度汽车零部件制造技术。E-mail:sophiacjy@ysu.edu.cn
  • 作者简介:靳田野,男,1989年出生,博士研究生,主要从事新型纳米孪晶材料刀具研制方面的研究。E-mail:jintianye3030@163.com
  • 基金资助:
    国家自然科学基金(51775482)和河北省自然科学基金(E2016203372)资助项目。

Material Removal Mechanism of Nanotwinned Cubic Boron Nitride by Femtosecond Laser Ablation

JIN Tianye1, CHEN Junyun2, WANG Jinhu1, ZHAO Qingliang1   

  1. 1. Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001;
    2. College of Vehicles and Energy, Yanshan University, Qinhuangdao 066004
  • Received:2018-04-19 Revised:2018-10-16 Online:2019-05-05 Published:2019-05-05

摘要: 为实现能应用于超精密切削的新型超硬纳米孪晶立方氮化硼(nt-cBN)刀具的制备,探索了飞秒激光烧蚀方法对nt-cBN的材料去除特性。使用激光单点烧蚀方法及理论公式计算出了nt-cBN的烧蚀阈值及阈值功率,分别为0.523 J/cm2和4.1 mW;基于烧蚀阈值,对nt-cBN材料在多种烧蚀功率下的单点烧蚀圆孔形貌进行了表征,并分析了不同阶段圆孔内壁多种微结构的形成与演变机理,阐明了随激光功率增加,nt-cBN表面经历了快速热汽化、熔化和相爆炸三种材料去除机理,并形成了纳米驼峰、爆裂和周期性波纹等不同烧蚀显微结构;对nt-cBN块材进行了直线扫描烧蚀加工,提出了基于光束扫描的动态烧蚀过程对材料的破坏形式及去除原理,并与单点烧蚀形成对比;建立了不同烧蚀功率下,飞秒激光扫描速度与加工微槽宽度和深度的关系曲线,并分析了烧蚀功率和扫描速度对加工效率和加工质量的影响规律,提出了能够保证加工效率并同时改善加工质量的激光扫描速度在0.1 mm/s左右。

关键词: 飞秒激光, 纳米孪晶立方氮化硼, 烧蚀阈值, 周期性微结构

Abstract: To fabricate the cutting tool of newly developed nanotwinned cubic boron nitride (nt-cBN) bulk applying for ultra-precision cutting, material removal mechanism of femtosecond ablation is studied. Damage threshold and the corresponding threshold power of nt-cBN are calculated by function relationship computation with single point ablation experiment, namely 0.523 J/cm2 and 4.1mW. Based on damage threshold, morphology and formation mechanism of ablation areas by multiple laser powers is analyzed, especially of the microstructure on the wall of micro holes. Rapid evaporation, fusion and phrase explosion are three main material removal mechanisms as accelerating laser power when machining nt-cBN surface. Nano humps, explosive cracks and periodicity ripples are found during different machining stages. Microgrooves are etched on nt-cBN surface by line scanning ablation. Dynamic material damage characteristics and removal mechanism in terms of scanning ablation are studied compared with single point ablation. The relation curve graphs between scanning speeds and the length and depth of microgrooves under different laser power are established respectively. The influence of laser power and scanning speed on ablation surface quality is analyzed. Scanning speed of about 0.1mm/s is proved beneficial for both high processing efficiency and well ablation quality.

Key words: damage threshold, femtosecond laser, nanotwinned cubic boron nitride, periodicity micro structure

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