Wire-Arc Directed Energy Deposition of High Performance Heat Treatment Free Al-6mg-0.3sc Alloy

Abstract

The release of residual stress during heat treatment of additively manufactured components could lead to significant deformation, particularly for those with thin-wall features and variable cross-sections. In this study, high performance heat treatment free Al-6Mg-0.3Sc alloy components were fabricated using the wire-arc directed energy deposition (Wire-arc DED) technique. The results demonstrate that, without heat treatment, the alloy exhibits remarkable mechanical properties, boasting a yield strength of 223.0±0.9 MPa, a tensile strength of 408.5±3.2 MPa, and an elongation of 20.6±1.7%. Employing characterization methods at different scales, a novel correlation between droplet transition, porosity, and microstructural evolution was established, shedding new light on the influencing factors of different arc modes on the performance of the as-deposited components. The findings presented herein demonstrate the promising application of wire-arc DED for direct manufacturing of oversized thin-walled components that can be deployed without the need for heat treatment.

Keywords: Al-6Mg-0.3Sc alloy, Wire-arc directed energy deposition, Mechanical properties, Microstructures, Arc mode