K4169 alloy is widely used to fabricate the stator component of aeroengine. In order to improve the high-temperature fatigue property of K4169 alloy

notch specimens for rotating bending fatigue were treated by the combination processing of laser shock peening (LSP) and shot peening (SP). The fatigue lives of single SP and combination processing (LSP+SP) were compared and analyzed. The fatigue fracture

three-dimensional surface morphology

roughness

surface residual stress and microhardness distribution were characterized by scanning electron microscopy (SEM)

white light interferometer

X–ray diffractometer and microhardness

tester. The mechanism of the combination processing on the fatigue performance was also investigated. The results indicate that the LSP+SP treatment shows better improvement of fatigue life than that of SP under the 647℃

450MPa conditions. After LSP+SP

the number of fatigue crack source decreases

and the location of the main source transferred from the surface to the subsurface. Moreover

the fatigue crack growth rate also decreases. In addition

the micro-stress concentration factor K

t

of the surface decreased from 2.39 to 1.46

and the surface residual compressive stress increased from –258MPa to –1140MPa. A work hardening layer with the depth of about 0.20mm was also generated. The improvement of fatigue life is considered to be mainly ascribed to the change of above surface integrity parameters.