抄録
Rotary bending fatigue tests using double ultrasonic shot-peened (USPed) magnesium alloy AZ61 were performed to investigate the effect of double ultrasonic shot peening (USP) on fatigue behavior. Double USPed specimens were USPed under the condition of the shot diameter, φ1.0mm and the coverage, 300%, and then USPed under the condition of the shot diameter, φ0.6mm and the coverage, 300%. The fatigue strength of double USPed specimen was highly improved compared with not only the base metal but also the single USPed specimens under the same condition of the first and the second USP of the double USP. It is considered that the improvement of fatigue strength of double USPed specimen is attributed to the enough increase in hardness and compressive residual stress in the first treatment and the decrease of surface roughness in the second treatment.
