Fracture Mechanisms of Aluminum Alloy Caused by Fatigue Tests

Fatigue damage is one of the key degradation mechanisms affecting the service life and reliability of aluminum alloys in a wide range of technical applications. The present study focuses on the fracture mechanisms of aluminum alloys under cyclic loading, with a view to the initiation and analysis of fatigue crack propagation in the context of the microstructural characteristics of the material. Special attention was paid to the influence of grain morphology, distribution and type of intermetallic phases, as well as the presence of casting defects on the initiation and development of cracks. Fatigue experiments were performed on a selected Al-Mg alloy of the EN AC 51200 type for the use of three-point bending loading. The results show that the key factors affecting the fatigue behavior are the size and distribution of precipitates, the nature of the interfaces between the phases and the occurrence of microcracks initiated mainly in areas of stress concentration. The knowledge gained contributes to a deeper understanding of fatigue mechanisms in aluminum alloys and provides a basis for their optimization in terms of composition and technological processing in order to increase their resistance to fatigue failures.