Effect of titanium powder on microstructure and mechanical properties of wire plus arc additively manufactured Al-Mg alloy

Al-Mg alloy thin wall components were fabricated with wire + arc additive manufacturing (WAAM) by feeding ER5356 wires and adding titanium powder. The microstructure and mechanical properties were analyzed, and the results showed that the phase Al3Ti formed provides heterogeneous nucleation cores, which contributed to the refinement of interlayer grains, transition of the crystal type from columnar to equiaxed, and increase of the fraction of low angle grain boundaries. Comparing thin wall components with and without titanium powder, the ultimate tensile strength and elongation of those with titanium increased in the vertical and horizontal direction. The micro-hardness of the interlayer was enhanced by 5-10 HV. With the addition of titanium powder, the mechanical properties of the WAAM Al-Mg alloy exhibited more isotropic characteristics in both directions. (C) 2019 Elsevier B.V. All rights reserved.