EFFECT OF SCRATCHES ON THE FATIGUE BEHAVIOR OF AN AL-LI ALLOY

An experimental investigation of the effects of small surface scratche s on the fatigue behavior of Al-Li alloys has been carried out. Small scratches were generated onto the specimen surface which were then sub jected to fatigue testing. These scratches were characterized by three different parameters, scratch angle, scratch tip radius of curvature, and scratch depth. These parameters have exhibited an important influ ence on the fatigue life of the scratched samples. In particular, it w as found that the fatigue life decreased sharply as the scratch depth increased. In addition, the scratch surface and fracture surfaces were examined under a scanning electron microscope. The observations helpe d in the assessment and identification of the mechanisms responsible f or failure.