Deposition process optimization and microstructure evolution of aluminum alloy produced by wire arc additive manufacturing

This study independently develops a software system with adaptive compatibility to the hardware platform. Based on this, wire arc additive manufacturing (WAAM) of 4043 aluminum alloy thin-walled components is conducted, and forming process parameters are optimized. According to the average melt width and residual height of single-pass single-layer deposits, the optimal parameters are determined as welding speed 8 mm/s and wire feeding speed 3.5 m/min. The optimized interlayer cooling time is set to 240 s for the bottom layer, 120 s for the middle layer, and 60 s for the top layer. Microstructural observations reveal banded fusion lines at adjacent layer interfaces, with denser interlayer regions featuring developed dendrites. Si phase granulation occurs in the upper region; the middle region has smaller grains dominated by heterogeneous grains, while the upper region consists mainly of columnar grains. Microhardness reaches a minimum of 74.7 HV in delamination zones and rises to 80.4 HV in interlayer regions, with fluctuations gradually weakening as layer thickness increases.