涡轴发动机燃气涡轮叶片热腐蚀机理分析与改进

目的 提高航空发动机燃气涡轮工作叶片的结构完整性、安全性和可靠性。方法 以某型涡轴发动机燃气涡轮转子叶片热腐蚀案例为研究对象，详细阐述热腐蚀下燃气涡轮转子叶片的结构破坏形式，分析发生热腐蚀部位的分布规律。通过冶金分析方法，研究燃气涡轮转子叶片的热腐蚀-疲劳失效形式。结果 燃气涡轮叶片高摩擦系数的区域在高温燃气的冲刷效应以及热盐腐蚀的作用下，发生表面涂层腐蚀剥落。涂层腐蚀剥落部分的叶片合金基体受到高温燃气的氧化与侵蚀后，形成了热腐蚀坑。腐蚀坑表面的凹凸处出现应力集中，并萌生裂纹，最终引起叶片疲劳断裂。结论 探究了典型腐蚀性物质对燃气涡轮转子叶片的耐高温涂层与镍基合金基体侵蚀与氧化的化学本质，最后针对燃气涡轮转子叶片热腐蚀问题提出了改进建议，可对防范航空涡轴发动机热腐蚀问题提供有益参考。

Hot Corrosion Analysis and Improvement of Gas Turbine Rotor Blades of Turboshaft Engines

In order to improve the structural integrity, safety, and reliability of the working blades of aviation engine gas turbines. This paper studied the hot corrosion-fatigue failure mechanisms of gas turbine rotor blades, including the structural failure mode, the distribution law of corrosion pits, as well as the erosion and oxidation mechanisms of thermal barrier coating and blade superalloy. The results showed that the surface coating corrosion spalling occurred in the high friction coefficient area of the gas turbine blade under the action of high temperature gas scour effect and hot salt corrosion. The corrosion pit was formed after the blade alloy substrate of the spalling part of the coating was oxidized and eroded by high temperature gas. The protrusions or depressions on the surface of corrosion pits caused stress concentration, which accelerated the initiation of fatigue cracks and finally lead to fatigue fracture of blades. The chemical nature of corrosion and oxidation of high temperature resistant coating and nickel-based alloy matrix on gas turbine rotor blades caused by typical corrosive substances is investigated. Finally, suggestions for improving the thermal corrosion of gas turbine rotor blades are put forward, which can provide useful reference for preventing the thermal corrosion of aviation turboshaft engines.