Experimental investigation of surface integrity and fatigue performance of TC17 alloy simulated blades under milling, polishing, vibration finishing, and shot peening conditions

The fatigue performance of blades directly governs the stability and reliability of aero-engines. This study focuses on fan integral blisk blades. A TC17 simulade blade was designed based on modal analysis and theoretical calculations, with subsequent investigation of surface integrity and fatigue performance under multi-process hybrid machining. Results demonstrate that the established relationship model between surface integrity and fatigue life exhibits excellent goodness-of-fit, evidenced by a coefficient of determination (R²) of 0.974. Fatigue cracks initiated from single or multiple surface origins in milled specimens, whereas precision-finished specimens exhibited single subsurface origins at depths of ∼ 30 μm. All shot-peened specimens displayed single subsurface crack initiation at depths of 56–100 μm. The fatigue life under SP processing exceeded that under M processing by 92 %. The crack initiation life accounted for 78–99 % of the total fatigue life in blades, with higher crack initiation life correlating directly with enhanced overall blade fatigue life. This work provides critical data for optimizing process parameters in TC17 fan integral blisk blade manufacturing, offering substantial implications for enhancing surface integrity and fatigue life performance during blade machining.