Analysis on Arc Additive Manufacturing Process and Microstructure of TiB₂/6056 Composites

The cold metal transfer (CMT)technology was used to study TiB₂/6056 wire additive manufacturing process on 6061 aluminum sheet.Taking the wire feeding speed and welding speed as the variables, the surface formation and microstructure of the additive layers under different heat inputs were observed and analyzed.The results show that it is beneficial to reduce the porosity of the composite additive weld bead by increasing the heat input.When the heat input is 1.2-2.4 kJ/cm, the weld bead is well formed with smooth surface and uniform ripples.With the increase of heat input, the weld width and reinforcement increase, and the microstructure of the additive layer changes from dendrite, cellular to equiaxed crystal.The fine TiB₂ particulates in the additive bead are mostly aggregated and distributed at the grain boundary of α-Al.