Fabrication of Single Crystals through a µ-Helix Grain Selection Process during Electron Beam Metal Additive Manufacturing
Martin R. Gotterbarm, Alexander M. Rausch, Carolin Körner
Abstract
Selective Electron Beam Melting (SEBM) is a powder bed-based additive manufacturing process for metals. As the electron beam can be moved inertia-free by electromagnetic lenses, the solidification conditions can be deliberately adjusted within the process. This enables control over the local solidification conditions. SEBM typically leads to columnar grain structures. Based on numerical simulation, we demonstrated how technical single crystals develop in IN718 by forcing the temperature gradient along a µ-Helix. The slope of the µ-Helix, i.e., the deviation of the thermal gradient from the build direction, determined the effectiveness of grain selection right up to single crystals.
Topics & Concepts
Cathode rayMaterials scienceHelix (gastropod)FabricationMetal powderBeam (structure)ThermalTemperature gradientMetalElectronCrystallographyMetallurgyOpticsChemistryThermodynamicsPhysicsGeologyPaleontologyAlternative medicineSnailQuantum mechanicsPathologyMedicineAdditive Manufacturing Materials and ProcessesAdditive Manufacturing and 3D Printing TechnologiesAluminum Alloy Microstructure Properties