Fatigue Fracture Behavior of TA15 Alloy after Laser Marking

Abstract

In order to study the effect of laser marking on the fatigue properties of TA15 titanium alloy, the alloy was marked at two depths respectively, and the low-cycle fatigue properties and fracture mechanism of TA15 titanium alloy after marking were analyzed and discussed. The results show that different degrees of marking pits appear on the surface of the alloy after laser marking, which is easy to cause local stress concentration. With the increase of power, the cross section shape of the bottom end of laser marking changes from a semi-arc shape to a sharp cone shape, resulting in high stress concentration phenomenon. The low cycle fatigue life of laser shallow marking specimens decreases by 62.7%, and that of laser deep marking specimens decreases by 86.4%. With the increase of the marking depth, the fatigue source area gradually becomes rough from smooth at the beginning, the divergence degree of cracks increases, the spacing of each crack in the initiation area increases, and the morphology becomes rough. The deeper the marking area is, the more driving force is provided for the initiation of cracks, and finally the fatigue performance deteriorates significantly.