(1. 南京航空航天大学 机电学院，南京 210016；
2. 中国直升机设计研究所，景德镇 333001)
摘 要: 采用以酒石酸钠为成膜剂的电解体系对0.5 mm厚的TB8钛合金薄板进行阳极氧化处理，采用扫描电镜(SEM)观察疲劳断口及氧化膜的显微形貌，采用X射线衍射仪(XRD)、能谱分析仪(EDS)对覆在钛合金基体上的阳极氧化膜进行物相分析，研究以酒石酸钠为成膜剂的TB8钛合金薄板阳极氧化疲劳断裂机理。结果表明：阳极氧化处理后，表面形成了一层厚2 μm左右的均匀致密的氧化膜，氧化膜主要由金红石型与锐钛型TiO2混合晶体组成；阳极氧化处理可有效去除表面缺陷，降低了裂纹源的萌生及疲劳裂纹的扩展速率，使疲劳条纹更加均匀细致；以酒石酸钠为成膜剂制备的TB8钛合金薄板经阳极氧化处理，在疲劳寿命为1×104下，其疲劳强度相对于母材的提高了44%左右。
关键字: TB8钛合金；阳极氧化；疲劳性能；断口形貌
（1. College of Mechanic and Electronic Engineering, Nanjing University of Aeronautics and Astronautics,
Nanjing 210016, China;
2. China Helicopter Research and Development Institute, Jingdezhen 333001, China）
Abstract:Anodic oxidation of 0.5 mm-thickness TB8 titanium alloy sheet in the electrolyte system with sodium tartrate as film-forming agent was investigated. The microstructures of the fatigue fracture and the anodic oxide films were observed by scanning electron microscopy (SEM). Meanwhile, the phase composition of the oxide films on the titanium alloy substrate was determined by X-ray diffractometry (XRD) and energy dispersive spectrometry (EDS).The fatigue fracture mechanism of both unanodized and anodized TB8 titanium alloy sheet was investigated in the film-forming agent of sodium tartrate. The results show that, a uniform dense oxide film about 2 μm-thickness forms on the surface after anodic oxidation, the coating is composed of rutile TiO2 and anatase TiO2. The surface defects are eliminated effectively, the initiation and propagation rate of the crack source reduce, resulting in the fatigue striations more uniform and detailed. The fatigue strength of TB8 titanium alloy sheet after anodic oxidation in the film-forming agent of sodium tartrate, increases by about 44%, compared with the base metal at the fatigue life of 1×104 cycles.
Key words: TB8 titanium alloy; anodic oxidation; fatigue property; fracture morphology
