High cycle fatigue properties of explosively welded laminate AA2519/AA1050/Ti6Al4V

The paper presents preliminary results of high cycle fatigue properties, including fatigue cracking of layered laminate AA2519/AA1050/Ti6Al4V. The test material was obtained by the method of explosive bonding in direct configuration AA2519/Ti6Al4V with the intermediate layer using a AA1050 alloy. The study tested influence of the applied heat treatment on the mechanical properties of the laminate. Load applied during the tests was oscillating sinusoidal with the stress ratio R=0.1 and constant load frequency equal to 20 Hz. The tests were performed at five levels of stress amplitude dependent on shape of samples. Assumed as the criterion for the end was the number of cycles at specimen failure or when number of cycles was equal to 5 million repeats. The results indicated the beneficial effect of the applied heat treatment. The results showed an increase the fatigue of the heat-treated samples, both notched and smooth samples. The results of electron microscopy studies of surface fatigue fracture allowed to determine the location of sources of fatigue cracking, which in the case of samples without heat treatment were in the area of border merger Ti6Al4V/AA1050. Sources of cracking in the elements after the heat treatment were located within the edge of the samples.