岛礁环境对吊耳疲劳性能影响研究

目的 研究吊耳在岛礁环境下的腐蚀特征及其对疲劳性能的影响。方法 通过开展吊耳试验件的岛礁自然环境试验，测试其不同在试验周期的疲劳性能，分析断口形貌、元素含量变化，研究腐蚀对吊耳抗疲劳性能的影响。结果 在1 a的岛礁自然环境试验中，吊耳的腐蚀部位主要为表面镀层，并且呈非均匀腐蚀特征。随着试验时间的延长，吊耳平均疲劳断裂循环次数呈下降趋势，疲劳断口的韧性断裂特征减弱，并且氢含量有所增加。吊耳内部存在MnS夹杂物，位于韧窝底部。结论 吊耳表面点蚀坑、内部MnS夹杂物对疲劳载荷作用下裂纹的萌生和生长起到促进作用，降低了其抗疲劳性能，应加强腐蚀防护和质量控制。

Effect of Island-Reef Environment on Fatigue Performance of Lifting Lug

The work aims to study the corrosion characteristic of lifting lugs in island-reef environments and its effect on fatigue performance. By natural environment test of the lifting lug used for a missile in a typical island-reef environment, the fatigue performance of the lifting lug were tested by a variable amplitude fatigue test. At the same time, the fracture corrosion morphology and element content were analyzed to study the effect of the island-reef environment on the fatigue performance. The results showed that:after one year of natural environment test, corrosion occurred to the zinc-nickel layer on the lifting lug surface, which showed the characteristics of non-uniform corrosion. During the test period, as the time prolonged, the average fatigue fracture cycle times of the lug decreased, the ductile fracture characteristics of the fatigue fracture surface weakened, and the hydrogen content increased. MnS inclusions were found in the inner part of the lifting lug and located at the bottom of the ligament. The pitting pits on the surface of the lifting lug and the inclusion of MnS inside the lug can promote the initiation and growth of the crack under fatigue loading, and reduce the fatigue resistance of the lug. Therefore, the corrosion and quality control must be strengthened to improve the corrosion fatigue performance of lifting lugs.