Mechanism of liquid film migration and interface reaction in multi-layer aluminum sheets during brazing based on the homogenization annealing

The influence of precipitate distribution and strain on the microstructure of AA4343/AA3xxx/AA4343 multi-layer aluminum sheets was investigated using optical microscopy (OM), glow discharge optical emission spectrometry (GDOES), scanning electron microscope (SEM), transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). This study evaluates the microstructure evolution and brazing performance of multilayer aluminum sheets. This study evaluates the microstructural evolution and brazing performance of multi-layer aluminum sheets, with a particular focus on understanding the conditions that lead to the harmful process of liquid film migration (LFM) during brazing. The Bergstrom hardening model was used to calculate the dislocation density in the sheet. The dislocation densities at which LFM and full core recrystallization occurred were found to differ. The results reveal the mechanism of solid-liquid interaction of multi-layer aluminum sheets during brazing and clarify the driving force of LFM during brazing. Consequently, these results provide important insights for the design and theoretical research of functional layered aluminum sheets.