摘要
对TC4-DT钛合金在不同应力比下的疲劳裂纹扩展行为进行了研究,绘制出疲劳裂纹扩展速率和应力强度因子幅值ΔK之间的关系曲线,用SEM对断口形貌进行了观测。实验结果表明,随着应力比增加,裂纹扩展速率增加;应力比降低,da/dN曲线向高ΔK方向移动。预裂区主要是以微区解理断裂机制为主,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,快速扩展区的断口形貌呈韧窝型静载断裂特征。
The fatigue crack propagation behavior of TC4-DT alloy under different stress ratios was investigated and the fracture surfaces were observed using SEM.The relationship between the propagation rate da/dN and the amplitude of stress intensity factor（ΔK） was drawn using.The results show that the crack growth rate increases with the increase of stress ratio.The decrease of stress ratio makes da/dN curves move to the higherΔK range.The near-threshold propagation stage gradually disappears.The cracks in the fore-crack region are mainly in the form of micro-cleavage fracture and spread in the form of strip mechanism in the stable spread region with micro-cleavage fracture.The fracture mophology in the fast spread region is dimple-type dead-load fracture.
出处
《热加工工艺》
CSCD
北大核心
2010年第20期33-35,共3页
Hot Working Technology
关键词
应力比
钛合金
疲劳裂纹扩展速率
断口形貌
stress ratio
titanium alloy
fatigue crack growth rate
fracture morphology
