TB6钛合金高速铣削三维表面形貌及疲劳行为

摘要

钛合金高速铣削以高效率、高质量的优点而被广泛应用于航空航天工业.为了优化高速铣削中控制表面粗糙度的工艺参数,通过高速侧面铣削试验及疲劳试验,研究高速铣削参数对三维表面形貌和疲劳寿命的影响.通过疲劳试样断口观测,揭示表面形貌对疲劳裂纹产生的作用机制.研究表明:铣削速度优选范围为100～140m/min,每齿进给量优选范围为0.02～0.06 mm/z,可保障表面粗糙度在0.8 μm内.基于表面应力集中系数建立的疲劳寿命模型与实验结果的平均误差为6.25％.疲劳裂纹起源于试件已加工表面的相交棱处.%High-speed milling of titanium alloys is widely used in aviation and aerospace industries for its high efficiency and good quality.In order to optimize the machining parameters in high-speed milling TB6 titanium alloy,experiments of high-speed milling and fatigue were conducted to investigate the effect of parameters on 3D surface topography and fatigue life.Based on the fatigue fracture,the effect mechanism of surface topography on the fatigue crack initiation was proposed.The experiment results show that when the milling speed ranged from 100 m/min to 140 m/min,and the feed per tooth ranged from 0.02 mm/z to 0.06 mm/z,the obtained surface roughness were within the limit (＜0.8μm).Fatigue life decreased sharply with the increase of surface equivalent stress concentration factor.The average error of fatigue life between the established model and the experimental results was 6.25％.The fatigue cracks nucleated at the intersection edge of machined surface.