Metal Additive Manufacturing Conference - MAMC 2022

Keywords: Additive Manufacturing, Laser Powder Bed Fusion, AA5024, Zirconium, Tungsten Carbide, Alloy Modification, Aviation

Aluminium alloys have a wide range of applications, specifically in the areas of aviation and aerospace. However, conventional manufacturing processes often limit the complexity of the fabricated parts. With the use of additive manufacturing techniques, near net-shape parts with a great structural complexity can be produced. When it comes to manufacturing aluminium alloys with laser powder bed fusion (L-PBF), many issues can appear. These are mainly due to the intrinsic material properties of aluminium – e.g. a high laser reflectance, a low laser absorption and a high thermal conductivity – which make these alloys difficult to process. Moreover, some aluminium alloys, such as from the 2XXX series, are prone to hot cracking due to their wide solidification interval, leading to formation of different eutectic phases. Therefore, the addition of nanoparticles to pre-alloyed powders is currently of great interest in the research on AM of aluminium based alloys in order to enhance both material’s printability and mechanical properties. This study focusses on the modification of an Al-Mg-Sc-Zr alloy (AA5024). The effects of using in-situ alloying to add different particles, i.e. Zirconium Hydride (ZrH2) and Tungsten Carbide (TC) in different amounts, as well as the effects of different heat treatments on the mechanical properties are discussed. For this purpose, density, hardness and tensile strength were measured on samples in both conditions: as printed and heat treated. Microstructural analysis was performed with light microscopy and SEM-EBSD in order to analyse the effects of the addition of different amounts of nanopowders by in-situ alloying.