Investigation of the Structure of the Joint Zone in Ti/Al/Aluminum Alloy Composites Produced by Explosive Welding with Ultrasonic Treatment

The article presents the results of a study of the microstructure of the near-boundary regions of aluminum and the aluminum-magnesium alloy AMg6 in three-layer titanium-aluminum-aluminum alloy composites obtained by explosive welding with ultrasonic treatment. Using electron backscatter diffraction (EBSD) and focused ion beam (FIB) electron microscopy, it is shown that the AMg6 alloy exhibits a finer grain structure than pure aluminum. Directly at the interface with aluminum in AMg6, a recrystallized layer with a grain size of 0.2–0.3 µm was formed. The application of ultrasound during welding contributed to an increase in the thickness of the recrystallized layer in AMg6 from 1.7–1.9 µm to 5.4 µm. In the pure aluminum layer, the ultrasonic treatment facilitated grain refinement at the interface with the titanium layer, while a decrease in the density of low-angle boundaries was observed at the interface with AMg6.