Metallurgical interactions in solid/liquid diffusion couples of AA4343/ AA3xxx/AA4343 layered aluminum sheet

The effect of pre-stretching on solid-liquid interaction, microstructure and brazing performance of AA4343/ AA3xxx/AA4343 layered aluminum sheet during brazing at the atomic level (solid solution), nanoscale (dislo-cation) and micron level (grain boundary) are studied by glow discharge optical emission spectrometry (GDOES), scanning electron microscope (SEM), electron backscatter diffraction (EBSD) and transmission electron micro-scopy (TEM). The microstructure after brazing largely depends on the forming condition. The driving force of liquid film migration (LFM) is the reduction of stored deformation energy. The interaction between the liquid clad and solid core layers changes the elemental distribution and microstructure, which in turn affects the brazing performance of the sheet. The results reveal the mechanism of solid-liquid interaction of layered aluminum sheet during brazing and clarify the driving force of LFM of layered aluminum sheet during brazing. Consequently, these results provide important insights for the design and theoretical research of functional layered aluminum sheet.