Microstructure evolution of 1100 Al alloy multi-foils during ultrasonic additive manufacturing

Multi-annealed 1100 Al alloy foils were welded to form monolithic samples using the ultrasonic additive manufacturing (UAM) process at room temperature. 40%, 60%, 80% of the oscillation amplitudes were investigated at 20 kHz frequency and a constant contact pressure. Deformed microstructures were analyzed using low-resolution electron backscattered diffraction (EBSD). Evolution of fine equiaxed grains from an initial coarser grain structure was observed in the volume of Al alloy foils, and the extent of the grain refinement is proportion to oscillation amplitude. Additionally, the orientation image maps (OIM), polar figures (PF), and orientation distribution functions (ODF) of the samples are obtained. The characteristics of the crystallographic orientation were analyzed to find the effect of ultrasonic amplitude on the microtexture of the matrix material.