Enhancement of Fatigue Life Performance of Holed Specimen of Aluminum Alloy 2024-T3 by Local Plastic Deformation

The effect of local plastic deformation on the fatigue life in a holed specimen was investigated. The local plastic deformation was applied around the hole by inserting a pin into the hole, and the pin was removed before the testing. The material used was aluminum alloy 2024-T3. After removing the pin, there was a circular hole or elliptical hole in the center of the flat section of the specimen. Due to the application of local deformation, the fatigue life of holed specimens became longer. In particular, in specimens where the hole shape was made elliptical, the fatigue life was clearly improved. Hardness distribution around the hole was measured to understand the effect of the local plastic deformation on the fatigue life expansion. Consequently, it is concluded that the local plastic hardening and compression residual stress in the vicinity of the hole are the cause of the strengthening of the holed specimen.