航空学报 > 2022, Vol. 43 Issue (4): 525353-525353   doi: 10.7527/S1000-6893.2021.25353

热障涂层水助激光扫描加工试验

王斌1,2,3, 王海涛1,2, 王玉峰1,2, 张文武1,2   

  1. 1. 中国科学院 宁波材料技术与工程研究所 先进制造技术研究所, 宁波 315201;
    2. 浙江省航空发动机极端制造技术研究重点实验室, 宁波 315201;
    3. 中国科学院大学 材料科学与光电技术学院, 北京 100049
  • 收稿日期:2021-02-01 修回日期:2021-03-02 发布日期:2021-07-20
  • 通讯作者: 张文武 E-mail:zhangwenwu@nimte.ac.cn
  • 基金资助:
    中国科学院重点部署项目(ZDRW-CN-2019-01);浙江省重点研发计划择优项目(2020C01036);浙江省自然科学基金(LY18E050027);宁波市科技创新2025重大专项(2019B10074)

Water-assisted laser scanning machining test of thermal barrier coating

WANG Bin1,2,3, WANG Haitao1,2, WANG Yufeng1,2, ZHANG Wenwu1,2   

  1. 1. Institute of Advanced Manufacturing Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China;
    2. Key Laboratory of Aero Engine Extreme Manufacturing Technology of Zhejiang Province, Ningbo 315201, China;
    3. College of Materials Science and Opto-electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2021-02-01 Revised:2021-03-02 Published:2021-07-20
  • Supported by:
    Key Deployment Projects of the Chinese Academy of Sciences (ZDRW-CN-2019-01);Excellent Projects of Zhejiang Province (2020C01036);Natural Science Foundation of Zhejiang Province (LY18E050027);Science and Technology Innovation 2025 Major Project of Ningbo City (2019B10074)

摘要: 为了提升涡轮发动机的整体性能和可靠性,需要在带热障涂层(TBC)的单晶高温合金涡轮叶片上制备大量气膜冷却孔,激光加工是实现"先涂层后打孔"的优势加工手段。采用水助激光扫描加工方法,通过正交试验和单因素试验研究了各因素对TBC损伤程度和TBC材料去除率的影响关系,试验结果表明对涂层剥落损伤的影响程度由大到小依次为光斑重叠率、激光重复频率、激光器电流和水泵电压,当光斑重叠率为98%、激光重复频率为50 kHz、激光器电流为38 A、水泵电压为14 V时,可以避免TBC水助激光加工出现剥落损伤;对TBC材料去除率的影响程度由大到小依次为激光器电流、激光重复频率、水泵电压和光斑重叠率,当优选激光器电流为38 A、激光重复频率为15 kHz、水泵电压为14 V、光斑重叠率为80%时,TBC材料去除效率最高。分析了TBC水助激光加工涂层剥落损伤的形成原因是热应力和等离子体力学冲击共同作用的结果,同时水助激光加工产生的气泡空蚀会导致加工区域周边涂层颜色变白,影响范围约为59.5 μm,空蚀去除厚度约2.7 μm。以上研究为带热障涂层单晶高温合金涡轮叶片气膜孔水助激光高效低损伤加工提供了技术支撑。

关键词: 热障涂层, 水助激光扫描加工, 涡轮叶片, 气膜冷却孔, 损伤分析, 正交试验, 参数优化

Abstract: To improve the overall performance and reliability of turbine engines, it is necessary to drill a large number of air film cooling holes on the single-crystal superalloy turbine blades with Thermal Barrier Coating (TBC). Laser processing is an advantageous method to realize coating before drilling. By using the water-assisted laser scanning machining, the orthogonal test and the single factor test have been conducted to study the effects of various factors on the TBC damage and its material removal rate. The results show that the impacts of spot overlap rate, laser repetition frequency, laser current and the pump voltage on the coating damage are in descending order. When the spot overlap rate is 98%, the laser repetition frequency 50 kHz, the laser current 38 A and the pump voltage 14 V, the peeling damage can be avoided in TBC water-assisted laser processing. While the effects of laser current, laser repetition frequency, pump voltage and spot overlap rate on TBC material removal rate are in descending order. When the optimal laser current is 38 A, laser repetition frequency 15 kHz, pump voltage 14 V and spot overlap rate 80%, the material removal efficiency of TBC is the highest. It has been analyzed that the coating peeling damage in TBC water-assisted laser processing is resulted from the joint effects of thermal stress and plasma dynamical shock. Meanwhile, the bubble cavitation caused by water-assisted laser processing will whiten the color of the coating around the processing area, with an influence range of about 59.5 μm and the removal thickness of cavitation about 2.7 μm. The research above has provided technical support for efficient and low damage laser processing of gas film holes in single-crystal superalloy turbine blades with thermal barrier coating.

Key words: thermal barrier coating, water-assisted laser scanning machining, turbine blade, film cooling hole, damage analysis, orthogonal test, process parameter optimization

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