A Review of Wire Arc Additive Manufacturing of High Strength 7xxx Series Aluminium Alloys

Abstract

High strength 7xxx series aluminium alloys are widely utilized in the aerospace, automotive and other manufacturing industries due to their low cost, high specific strength, high stiffness strength and fracture toughness. Additive manufacturing presents new opportunities in producing 7xxx series aluminium alloys such as reduced material waste, shorter lead time, and increased design freedom. This paper reviews the current progress in Wire Arc Additive Manufacturing (WAAM) of 7xxx series aluminium alloys, a technology that offers benefits such as better energy absorption than alternative laser-based processes, high deposition rates, and unrestricted build size. A classification of the AM processes utilized to fabricate aluminium alloys and WAAM process variants for fabricating aluminium alloys are introduced. Also, some common defects including porosity, solidification cracking and volatile elements loss encountered during the WAAM process of 7xxx series aluminium alloys are discussed. Whilst porosity remains a major issue in 7xxx series aluminium alloys produced via WAAM, several opportunities to minimize or eliminate the defects through process selection and alloy development are presented.