Surface Integrity of TA19 Notched Simulated Blades with Laser Shock Peening and Its Effect on Fatigue Strength

摘要

To reveal the fatigue strengthening mechanism of TA19 notched simulated blades with laser shock peening (LSP), surface integrity and fatigue strength were investigated. The surface morphology, residual stress, near-surface microstructure, fatigue strength and fatigue fracture morphology were analyzed by surface profiler, x-ray diffraction (XRD), transmission electron microscopy (TEM), QRG-100 servo-hydraulic fatigue test machine and scanning electron microscope (SEM). Results indicated that LSP induced surface micro-dents plastic deformations with a few microns in depth, surface compressive residual stresses and surface nano-grains of TA19 notched simulated blades. Compared with the as-received material, fatigue strengths of TA19 notched simulated blades were improved by 162% for LSP-1 and 218% for LSP-3. In addition, fatigue crack initiation (FCI) locations reduced after LSP, fatigue crack growth (FCG) rate decreased after LSP, and secondary cracks were observed in the FCI and FCG regions of fatigue fracture morphologies after LSP. Fatigue strengthening mechanism of TA19 notched simulated blades with LSP was compressive residual stresses and refined grains. Results could be beneficial to the application of LSP process in civil engines blades.