Effect of Part Orientation and Low-Temperature Annealing on Impact Toughness of Laser Powder Bed Fusion-Processed AlSi10Mg

The V-notched specimens were additively manufactured from AlSi10Mg alloy powders using laser powder bed fusion technique with three different orientation conditions. The specimens were post-heat-treated at two temperature conditions, viz 270 and 320 °C, in order to improve its mechanical properties. The microstructures, hardness and toughness of the specimens were investigated by taking into account the effect of heat treatment temperatures, impact test temperatures and build orientations. The toughness obtained after heat treating at 270 and 320 °C was found to be considerably higher when compared to the as-printed specimens, with the heat treatment at 320 °C resulting in nearly twofold improvement over specimens annealed at 270 °C due to the precipitation of Mg2Si particles along with the disintegrated spherical Si particles. A transition from inter-track and interlayer mode of fracture to trans-track fracture is observed at lower temperature. The specimens annealed at 320 °C showing lower number of trans-track fractures as compared to specimens annealed at 270 °C.