Microstructure and properties of Al alloy ER5183 deposited by variable polarity cold metal transfer

Abstract Nine groups of wire arc additive manufacturing (WAAM) aluminum alloy walls with different layers were deposited by variable polarity cold metal transfer arc mode using ER 5183. Their microstructures were characterized by optical microscopy and electron back scattered diffraction. For the top layer, grain size increased from 37 μm to 65 μm, and then stabilized at around 41μm, in accordance with the decrease of microhardness from 98.7 HV to 76.4 HV. As the number of deposited layers increased, the anisotropy in the bottom layers was weaken, and small-angle grain boundary may cause an increment to 96.1HV in the microhardness before stabilized around 81HV due to the heat accumulation.