Abstract
Shot peening was adopted to strengthen the Fe-2Cu-2Ni-1Mo-1C sintered material. Effect of shot peening on microstructure, mechanical properties and fatigue performance was investigated. Results showed that shot peening strengthened the surface and improved surface density of the sintered material. The thickness of the surface dense layer achieved at 70 μm. The sintered material consists of pearlite, bainite and retained austenite. The tensile strength slightly increased after shot peening and reached at 699 MPa. Fatigue behavior of the material was studied by ultrasonic fatigue testing; results showed that shot peening improved the fatigue performance; under 107 cycles, the conditional fatigue limit of the shot peened specimen is 421 MPa, which increased by 35.2% comparing with those of the as-sintered specimen. Effect of shot peening on fatigue fracture was mostly in crack initiating stage; it forced the crack sources to be initiated at the sub-surface instead and delayed the initiation of fatigue crack.
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