摘要
按照GB6398-1986试验标准,采用紧凑拉伸试样(CT)测定了铸造Ti-6Al-4V钛合金疲劳裂纹扩展速率da/dN,采用扫描电镜(SEM)等现代技术对断口形貌进行观察,分析了不同应力比(R值)条件下的疲劳裂纹扩展特性。结果表明,应力比R对铸造Ti-6Al-4V钛合金的裂纹扩展速率影响较大,应力比R越大,裂纹扩展速率越大。在裂纹预裂区和快速扩展区的断裂机理主要是以微区解理断裂为主,稳态扩展区主要是以疲劳条带扩展机制为主,同时也存在微区解理断裂机制。
The fatigue crack growth rate （da/dN） for Ti-6Al-4V casting titanium alloy was obtained by measuring compact tension specimen according to the tested standard of GB6398-1986. Fracture was observed by SEM （scanning Election Microscope）, and the fatigue crack growth feature at different R values were discussed. The results show that stress ratio （R） affects the fatigue crack growth rate, and the da/dn increase with increasing R. At pre-plitting area and rapid propagation area are cleavage fracture, at steady growth area the fracture mechanism is fatigue braids mechanism, and cleavage fracture is also existed.
出处
《铸造技术》
CAS
北大核心
2010年第3期295-297,共3页
Foundry Technology
