Evolution of surface integrity and fatigue properties after milling, polishing, and shot peening of TC17 alloy blades

The surface integrity and fatigue properties of TC17 alloy blades under integrated manufacturing processes are investigated. The R-a values of milling-polishing (MP)-processed and milling-polishing-shot peening-vibration polishing (MPSV)-processed blades are less than 0.4 mu m. MPSV produces a strengthened layer about 100 mu m and a gradient microstructure. The modal analysis results obtained from finite element calculation corresponds well with the values measured experimentally. The fatigue lives of the MPSV-processed blades are increased by approximately 119.5% compared with the MP-processed blades. The fatigue fracture morphology indicates that fatigue cracks are initiated on the leading edge surface regardless of the processes employed.