Microstructure evolution and mechanical behavior of additively manufacturing of Al-Si alloy by cold metal transfer with interlayer adding La₂O₃ powder

Additive manufacturing of Al-Si alloy thin-walled components with/without interlayer adding La₂O₃ powder were obtained by cold metal transfer (CMT). Based on the optimisation of the CMT additive manufacturing process, the influences of La₂O₃ powder on the microstructure and properties of parts were analysed by using OM, SEM and EBSD. The results showed that by adding La₂O₃, the effective length and layer height of the component was increased due to the increase of the surface tension. Nucleation particles were increased by adding the La₂O₃, which resulted in that the α-Al and Al-Si eutectic were refined compared with that of no adding La₂O₃. By adding La₂O₃, the tensile properties of the part were improved. The refinement microstructure was the main reason for the improvement of mechanical behaviour.