The Effects of Machining-induced Surface Topography on Fatigue Performance of Titanium Alloy Ti-6Al-4V

摘要

Machining-induced surface integrity has an important effect on reliability and service life of the components used in the aerospace industry where titanium alloy Ti-6Al-4V is widely applied. Characterization of machining-induced surface integrity and reveal its effect on fatigue life are conducive to structural fatigue life optimization design. In the present study, surface topography was characterized in peripheral milling of titanium alloy Ti-6Al-4V. And then, low cycle fatigue performances of machined specimens were studied on the basis of the tension-tension tests. Finally, the regular pattern of influence on fatigue performances by cutting process parameters was discussed. Conclus ions were drawn that three-dimensional surface roughness parameters showed almost the same trend as two-dimensional ones under different cutting conditions, while fatigue life models based on surface stress concentration factor that calculated using three-dimensional surface roughness parameters are more accurate than that using two-dimensional ones. Through sensitivity analysis, it can be found that feed rate was the key factor to affect the fatigue life, followed by cutting speed and depth of cut, respectively.