Effect of surface scratches on the fatigue strength of 5083 aluminum alloy

Abstract

The fatigue strength of 5083-R and 5083-O sheet specimens of 6mm thickness having artificial scratches at the middle part was investigated. The scratch was made by scraping with a tool, having a tip angle of about 80° and a tip radius of about 0.02mm.
As the results of tests, the effect of scratches on the fatigue strength was not found for the scratch depth less than 0.06mm for 5083-R specimens and less than 0.10mm for 5083-O, and fatigue fracture always occurred at the other part than the scratches. For the specimens with the scratch depth more than the above mentioned, fatigue failure was initiated at the surface scratches and their fatigue strength was slightly decreased with increasing the scratch depth. The effect of the angle between the scratch and the direction of the alternating stress on the fatigue strength was not found from the fatigue tests of 5083-O specimens with the scratch depth less than 0.2mm.