Effects of surface defects on the fatigue strength of 7178 aluminum alloy

Abstract

Alternate bending tests were conducted on sheet specimens of 6 mm thickness having a stamped mark at the central part of surface. The fatigue strength at 10⁷ cycles of specimens having stamped depths 0.18, 0.28 and 0.43 mm decreases by 9, 15 and 23% respectively as compared with that of the smooth surface. The fatigue tests were also carried out on flat specimens with a small central hole. The notch sensitivity of 7178-T6 alloy is slightly less than that of 7075-T6 alloy reported by Fukai and Takeuchi.