To promote the fatigue property of the disk’s stress-concentration structure made by powder metallurgy uperalloy

cast-iron shots

ceramic beads and the compound of the two kinds of shots are employed to peen the PM notched atigue sample. Strengthening layer is characterized by surface profile analysis using white light interfere

residual stress measurement ith X-ray diffraction and electrochemical corrosion

and micro-hardness profile research. Fatigue strengthening effect s compared with high-temperature notched (structure stress-concentration coefficient Kt=1.7) fatigue life of rotating-bending ode. The results show that strengthening layer is introduced by shot peening on the surface of FGH95 alloy. After shot eening

the surface average roughness and Kurtosis value are 0.9–1.5μm and close to 3 respectively. Surface residual stress s about –800 – –1150MPa

and the depth is 120~250μm. Moreover

compared with the as-received hardness 480–510HV0.2

he peening surface hardness increased to 575–625HV0.2

and the hardness layer depth is 175–250μm. The double shot peening ethod

firstly using the cast-iron shot in big intensity and secondly using the ceramic shot in small intensity

brings the aximum residual compressive stress

the highest hardness and biggest depth on the surface

and the smaller roughness with mooth bottom of crater

which obtains the best fatigue strengthening effect. The median fatigue life estimations of the double hot peening at 550MPa/650℃ is 20 times higher than original one.