Influence of shot peening on notched fatigue strength of the high-strength wrought magnesium alloy AZ80

Influence of shot peening (SP) on notched fatigue strength of the high-strength wrought magnesium alloy AZ80 has been investigated by using different SP media (including glass, Zirblast B30 and Ce–ZrO2 (ZrO2 stabilized by Ce) shots) and various Almen intensities. The results showed that shot peening improved the notched fatigue strength of AZ80 more effectively than the un-notched fatigue strength. The notched fatigue strength of AZ80 increased from 45 to 110 MPa after optimum shot peening, regardless of particular peening media. Optimum SP conditions were obtained at high Almen intensities, implying that surface defects and high roughness induced by heavier SP played a tiny role on the notched fatigue strength of AZ80. Fatigue crack initiated on the surface of shot-peened specimens due to high stress concentration at notch root. Short cracks were observed in run-out shot-peened specimens, indicating that the beneficial effect of SP on notched fatigue strength of AZ80 was mainly caused by the compressive residual stresses, which can effectively retard/or even arrest the fatigue cracks.