模拟打伤/抛修缺口对TC17钛合金叶片振动疲劳性能的影响

研究了无缺口、打伤缺口和3种抛修缺口对TC17钛合金叶片振动疲劳性能的影响。结果表明,无缺口模拟叶片的疲劳寿命最长且寿命分散性最小,打伤缺口模拟叶片的疲劳寿命最短且寿命分散性最大,3种抛修缺口模拟叶片的疲劳寿命介于前两者之间,其中抛修缺口Ⅰ模拟叶片的疲劳寿命最长。无缺口和抛修缺口模拟叶片的疲劳裂纹均起源于叶片根部,打伤缺口模拟叶片的裂纹产生于缺口底部,与有限元模拟计算的最大应力位置吻合。模拟叶片的疲劳断裂区比较平坦,呈半椭圆形貌,疲劳源区主要位于模拟叶片表面的微小损伤处,疲劳扩展区具有典型的疲劳弧线特征,并呈现沿α/β片状组织界面开裂的特征。

Effect of Damaged and Repaired Notch on Vibration Fatigue Property of TC17 Titanium Alloy Simulated Blades

The effects of smooth(non-damaged),damaged and three kinds of polishing repaired notch structure on the vibration fatigue properties of TC17 titanium alloy simulated blades are investigated.The results show that smooth simulated blades exhibit the longest fatigue life and smallest life data dispersion,while the fatigue life of simulated blades with damaged notch are the smallest and the dispersion are the largest.The fatigue life increases when the damaged notch is repaired by polishing,the fatigue life of the blades with repaired notchⅠis the largest,but still less than the life of smooth blades.The fatigue cracks in both smooth and repaired blades initiate at blade roots,while in the damaged blades fatigue crack are found at the notch.The crack sites are consistent with the largest stress sites in FEM results.The fatigue fracture regions of simulated blades are flat,in half ellipse morphology.The crack initiations mostly derive from the surface tiny damage.Fatigue propagation regions are characterized by typical fatigue beaches,present the character that cracked along the interface of α/β lamellar microstructure.