Abstract: The performance, especially fatigue performance of powder metallurgy materials is relatively poor due to the existence of pores, and shot peening can evidently reduce the porosity of material surface and improve its fatigue performance. Consequently, focus of this article is to investigate the effect of shot peening on fatigue strength by ultrasonic fatigue test. Results show fatigue strength of Fe-2Cu-2Ni-1Mo-1C is increased evidently by shot peening. Under 106, 107, 108 cycles, the conditional fatigue limit of the sintered samples are 424 MPa, 311 MPa and 229 MPa, the conditional fatigue limit of the shot peened samples are 513 MPa, 421 MPa and 346 MPa, the fatigue limit is increased by shot peening by 21.0%, 35.2%和51.0% respectively. Fatigue fracture morphology show effect of shot peening on fatigue fracture is mostly in crack initiating stage, crack of sintered samples initiates in the edge. Crack of shot peened samples initiates in the sub-surface, crack sources trend to move to the sub-surface.

Key words: Fatigue fracture, Fatigue property, Powder metallurgy, Shot peening