The Analysis of Fatigue Crack Propagation in the Elements of Aluminum Alloy D16CZATW with a Notch in the Formof A Cylindrical Hole

In this work, the fatigue life of specimens made from the aluminum alloy D16CzATW has been determined. To this aim, flat specimens with notches in the form of cylindrical holes made by drilling and reaming have been investigated. The research was carried out under the conditions of constant-amplitude bending at the stress ratio of R = -1. The results obtained were compared with the fatigue life of specimens with calibrated holes and specimens without notches. Fatigue life was determined for specimens plated on both sides and those without this protecting layer. Very large differences in fatigue resistance were observed. These differences can be explained by the negative effect of the brittle protecting layer on the fatigue crack initiation process. A complex fracture mechanism was observed, in which micro-mechanisms of brittle and ductile fracture were appearing at different stages of fatigue crack propagation.