带型芯涡轮叶片激光电液束异步复合加工气膜孔的机理与工艺研究

The efficient manufacturing of high-quality film cooling holes on turbine blade in aero-engine is a key technical bottleneck which restricts the development of the domestic aviation field. Due to the rigorous service environment of the turbine blades, the film cooling holes are required to be free of recast layer/micro cracks and HAZ. In addition, the characteristics of high aspect ratio, large number and high inclination all make it very difficult to produce good cooling holes. Therefore, this project provide a kind of asynchronous combined machining technology of laser and jet electrochemical on turbine blade before the removal of ceramic core. This method makes full use of the advantages of laser and jet ECM, i.e. efficiency of laser and high quality of ECM, to realize the machining of cooling holes without recast layer. To reach this goal, three researches are to be carried out, including: the absorption and transfer mechanism of laser energy in drilling of holes with high aspect ratio and high inclination, so as to understand the energy conversion form and its laws; The migration mechanism of molten material in laser drilling assisted by the ceramic base and the controllability of recast layer, so as to disclose the change law of hole shape and recast layer quantitatively; The characteristics of flow field and electric field when jet ECM is impact the laser drilled hole and the mechanism of dissolving of recast layer, so as to get the optimized jet ECM parameters. It is expected that film cooling holes without recast layer can be efficiently produced by the conduction of this project, and the domestic high-end manufacturing ability can be promoted.

航空发动机涡轮叶片气膜冷却孔高效高质量加工是一项长期制约我国航空制造业发展的关键技术瓶颈，涡轮叶片恶劣的服役环境要求气膜孔必须做到无重铸层、无微裂纹、无热影响区，而且气膜孔孔径小、数量多、倾角大，加工难度极大。本项目提出了一种带陶瓷型芯涡轮叶片激光-电液束异步复合加工气膜孔的新方法，该方法充分利用了激光加工高效和电液束加工高质量的优点，可实现无重铸层气膜孔加工。为此，本项目将展开三方面的研究，包括：激光冲击大倾角大深径比气膜孔时的能量吸收与转化机制，以明确激光加工过程中的能量转换形式及其规律；陶瓷衬底约束下激光打孔过程材料迁移机制与重铸层可控性研究，以揭示孔深度和重铸层厚度的定量变化规律；电液束高速冲击预制时的流场电场特性及其对重铸层融解机制，以掌握电液束高效去除激光预制孔壁重铸层的内在机制，并得到最优化的电解工艺参数。通过本项目的研究实现无重铸层气膜孔高效加工，推动我国高端制造业进步。

航空发动机涡轮叶片气膜冷却孔高效高质量加工是一项长期制约我国航空制造业发展的关键技术瓶颈，涡轮叶片恶劣的服役环境要求气膜孔必须做到无重铸层、无微裂纹、无热影响区，而且气膜孔孔径小、数量多、倾角大，加工难度极大。本项目提出了一种带陶瓷型芯涡轮叶片激光-电液束异步复合加工气膜孔的新方法，该方法充分利用了激光加工高效和电液束加工高质量的优点，实现了无重铸层气膜孔的加工。本项目主要研究了高功率激光加工初始气膜孔时的能量转换形式及其规律，以及激光打孔过程中材料迁移机制与重铸层可控性研究，揭示了孔深度和重铸层厚度随加工参加的变化规律，并利用调制激光打孔技术高效加工出了重铸层小于10μm的预制孔；搭建了激光电液束异步复合加工实验平台；研究了电液束加工参数对孔壁重铸层去除效果的的影响规律，实现了无重铸层、无微裂纹、无热影响区气膜孔的加工，单孔加工时间小于20s，相比传统电液束加工，效率得到大幅提升。本项目的完成为我国航空发动机叶片气膜冷却孔制造提供了一种新的具有可行性的技术手段，其完善后的推广应用将有利于提升国产航空发动机的寿命和可靠性，缩短装备生产周期，具有重要的经济和社会意义。本项目研究了高功率激光加工预制气膜孔时的能量转换形式，以及激光打孔过程中材料迁移机制与重铸层可控性研究，揭示了孔深度和重铸层厚度随加工参加的变化规律，并利用调制激光打孔技术高效加工出了重铸层小于10μm的预制孔；搭建了激光电液束异步复合加工实验平台；研究了电液束加工参数对孔壁重铸层去除效果的的影响规律，实现了无重铸层、无微裂纹、无热影响区气膜孔的加工，单孔加工时间小于20s，相比传统电液束加工，效率得到大幅提升。本项目的完成为我国航空发动机叶片气膜冷却孔制造提供了一种新的具有可行性的技术手段，其完善后的推广应用将有利于提升国产航空发动机的寿命和可靠性，缩短装备生产周期，具有重要的经济和社会意义。