Abstract: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 (<0.8 μm). 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.

Key words: TB6 titanium alloy; high-speed milling; surface roughness; surface topography; fatigue life; fatigue fracture