Effects of post-deposition heat treatment on microstructures of GTA-additive manufactured 2219-Al

Abstract

Several 2219-Al parts were produced by GTA (Gas Tungsten Arc) additive manufacturing, then an exceptional heat treatment characterised by long solution time was proposed and carried out to improve their microstructures and mechanical properties. Results show that, for the macroscopic features, the regional-division and layered-division features are eliminated after the heat treatment. For the microstructures, grain morphologies remain almost the same after the heat treatment, but the sizes and distributions of both eutectics and particles change significantly. The net-like and bulk-like eutectics are dissolved into point-like structures, while uniformly distributed θ′ – particles precipitate out. For the hardness, the heat treatment brings about significant precipitation strengthening, leading to a 97% increase of the Vickers hardness of GTA-additive manufactured 2219-Al.