Investigating fatigue life degradation of TC11 titanium alloy in hot salt corrosion environment

TC11钛合金热盐腐蚀环境下疲劳寿命衰减规律研究

¹ School of Power and Energy, Northwestern Polytechnical University, Xi'an 710072, China
² Wuxi Trumy Transmission Engineering Co., Ltd., Wuxi 214111, China

Received: 26 October 2024

Abstract

The fatigue life degradation of the TC11 titanium alloy in the hot salt corrosion environment, which is commonly used in aero-engine compressor components, was investigated. Hot salt corrosion fatigue tests were conducted within the temperature and load range of an aero-engine compressor component. The results show that the fatigue life of the TC11 titanium alloy in the hot salt corrosion environment significantly decreases by 1 to 2 orders of magnitude compared with the non-corrosion life at 450 ℃ and that the dispersion was relatively large. The corrosion life of hot salt at different temperatures shows a similar pattern, but with the increase of temperature, the corrosion is more intense, and the fatigue life decreases greatly. The failure mechanism analysis of corrosion fatigue fracture specimens was also conducted. The results show that unlike the traditional non-corrosive mechanical fatigue, which mostly has a single-source crack initiation, the hot salt corrosion fatigue has an obvious multi-source crack initiation under high stress. Finally, the hot salt corrosion fatigue life prediction model of the TC11 titanium alloy based on the damage mechanics method was established, taking into consideration the coupling relationship between mechanical damage and corrosion environment damage. All the prediction results are within the double dispersion band of the test life of the TC11 titanium alloy, indicating that the model can well predict its hot salt corrosion fatigue life.

摘要

针对航空发动机压气机部件常用的TC11钛合金, 开展了热盐腐蚀环境下疲劳寿命衰退规律研究。在某型发动机压气机部件温度与载荷范围内开展了热盐腐蚀疲劳试验, 结果表明热盐腐蚀环境下TC11疲劳寿命显著衰减, 对比450 ℃下无腐蚀寿命, 热盐腐蚀疲劳寿命下降1~2个数量级, 且分散性较大。不同温度下热盐腐蚀寿命都呈现相似的规律, 但是随着温度的升高, 腐蚀对寿命衰减的影响更剧烈, 疲劳寿命下降程度更大。对腐蚀疲劳断裂试样开展了失效机理分析, 与传统的无腐蚀机械疲劳多为单一裂纹源不同, 热盐腐蚀疲劳有着明显的多源裂纹特征。建立了基于损伤累积方法的TC11钛合金热盐腐蚀疲劳寿命预测模型, 考虑了力学损伤和腐蚀环境损伤之间的耦合关系, 预测结果都在试验寿命的2倍分散带内, 表明模型能够很好地预测TC11钛合金的热盐腐蚀疲劳寿命。