Abstract
Fretting fatigue behavior of an extruded AZ61 magnesium alloy was studied. Plain fatigue test and fretting fatigue test had been conducted at relative humidity of 30-65%RH and 80%RH. Fatigue strength under plain fatigue was 140MPa and that under fretting fatigue with contact pressure of lOOMPa was 40MPa at 10^8cycles in humidity of 30-65%RH. Crack initiated at the edge of the contact region due to the singularity stress field near the contact edge. Crack initiation life was only 1.0〜-2.5% of total fretting fatigue life. Fretting fatigue strength at 10^8 cycles decreased to 20MPa under 80%RH. Corrosion pits were found at the fracture origin in the high humidity condition with low stress amplitude.
