ZTC4(Ti-6Al-4V)铸造钛合金的室温低周疲劳行为

Low Cycle Fatigue Behavior of ZTC4(Ti-6Al-4V) Titanium Alloy at Room Temperature

研究了ZTC4钛合金应变控制的室温低周疲劳行为,对循环应力-应变和应变疲劳寿命数据进行了分析,通过双对数线性回归处理,得出了Manson-Coffin处理模型的疲劳参数。结果表明:ZTC4钛合金总应变幅在0.6%～0.8%时,材料存在轻度循环软化的现象;总应变幅为0.4%～0.5%时,循环初期表现出循环硬化的现象,而后循环软化。合金的疲劳裂纹萌生于试样表面,裂纹扩展区存在明显的疲劳条带,合金疲劳断口呈现韧性断裂特征。

Low cycle fatigue（LCF） behavior of ZTC4 titanium alloy has been investigated under fully reversed total strain-controlled mode.The cyclic stress-strain and strain-life data were analyzed to determine the individual strain fatigue parameters of Manson-Coffin model by double logarithm linear regression processing.The results showed that the ZTC4 titanium alloy exhibited an initial slight cyclic hardening,followed by cyclic softening at the total strain amplitude of 0.4%-0.5%,then cyclic softening at a total strain amplitude of 0.6%-0.8%.The fatigue cracks initiated at the surface of the samples.The fatigue crack propagation regions were composed of fatigue striations.The fatigue fracture surface of specimens revealed the fracture characteristics of dimple.