Targeting biomedical applications, Triply Periodic Minimal Surface (TPMS) gyroid sheet-based structures were successfully manufactured for the first time by Electron Beam Melting in two different production Themes, i.e., inputting a zero (Wafer Theme) and a 200 µm (Melt Theme) wall thickness. Initial assumption was that in both cases, EBM manufacturing should yield the structures with similar mechanical properties as in a Wafer-mode, as wall thickness is determined by the minimal beam spot size of ca 200 µm. Their surface morphology, geometry, and mechanical properties were investigated by means of electron microscopy (SEM), X-ray Computed Tomography (XCT), and uniaxial tests (both compression and tension). Application of different manufacturing Themes resulted in specimens with different wall thicknesses while quasi-elastic gradients for different Themes was found to be of 1.5 GPa, similar to the elastic modulus of human cortical bone tissue. The specific energy absorption at 50% strain was also similar for the two types of structures. Finite element simulations were also conducted to qualitatively analyze the deformation process and the stress distribution under mechanical load. Simulations demonstrated that in the elastic regime wall, regions oriented parallel to the load are primarily affected by deformation. We could conclude that gyroids manufactured in Wafer and Melt Themes are equally effective in mimicking mechanical properties of the bones.

Electron beam powder bed fusion (PBF-EB) is a known metal additive manufacturing (AM) technology. Processing non-conducting powders such as ceramics has so far been considered as not feasible because of the inherent problems with Coulomb repulsion due to insufficient electrical conductivity. In this study, a method for functionalizing ceramic powder is proposed where particles are electroless coated by a ~ 1 µm Ni layer to decrease the surface resistivity. The feasibility of the suggested approach is tested on Al₂O₃ powder, and the results show that the coated ceramic powder has a decreased surface resistivity, which enables processing by PBF-EB. Heating and melting parameters were investigated and samples were manufactured at ~ 1600 °C. Sintered and melted powders were analyzed by microscopy and micromechanically tested by nanoindentation. Calculations, visual observation and SEM–EDX suggest that the Ni coating is evaporated during the process, which suggests that the process could be feasible for the manufacturing of pure ceramic parts.

In this work, a highly alloyed cold work tool steel, Uddeholm Vanadis 4 Extra, was manufactured via the electron beam melting (EBM) technique. The corresponding material microstructure and carbide precipitation behavior as well as the microstructural changes after heat treatment were characterized, and key mechanical properties were investigated. In the as-built condition, the microstructure consists of a discontinuous network of very fine primary Mo- and V-rich carbides dispersed in an auto-tempered martensite matrix together with ≈15% of retained austenite. Adjusted heat treatment procedures allowed optimizing the microstructure by the elimination of Mo-rich carbides and the precipitation of fine and different sized V-rich carbides, along with a decrease in the retained austenite content below 2%. Hardness response, compressive strength, and abrasive wear properties of the EBM-manufactured material are similar or superior to its as-HIP forged counterparts manufactured using traditional powder metallurgy route. In the material as built by EBM, an impact toughness of 16–17 J was achieved. Hot isostatic pressing (HIP) was applied in order to further increase ductility and to investigate its impact upon the microstructure and properties of the material. After HIPing with optimized protocols, the ductility increased over 20 J.

Metal additive manufacturing technologies, such as electron beam powder bed fusion (PBF-EB), rely on layer heating to overcome the so-called “smoke” phenomenon. When scaled up for industrial manufacturing, PBF-EB becomes less productive due to the lengthy preheating process. Currently, only the electron beam (EB) is used for preheating in PBF-EB, resulting in increased manufacturing times, energy consumption, and in some cases limiting the applicability of the technology. In this study, a new preheating approach is suggested that incorporates a near-infrared radiation (NIR) emitter inside an PBF-EB system. The NIR unit eliminates the need for EB heating, reducing build time and powder charging. Successful builds using 316 L and Ti6Al4V precursor powders validate the feasibility of the proposed approach. The produced samples exhibit similar properties to those obtained by the standard PBF-EB process. The introduction of NIR technology also reduced build cost and increased the service intervals of the electron gun.

The use of an electron beam (EB) as a heating source in EB-based powder bed fusion (PBF-EB) has several limitations, such as reduced powder recyclability, short machine service intervals, difficulties with heating large areas and the limited processability of charge-sensitive powders. Near-infrared (NIR) heating was recently introduced as a feasible replacement and/or complement to EB heating in PBF-EB. This work further investigates the feasibility of using NIR to eliminate the need for a build platform as well as to enable easier repairing of parts in PBF-EB. NIR-assisted Ti-6Al-4V builds were successfully carried out by starting from a loose powder bed without using a build platform. The results do not only confirm that it is possible to eliminate the build platform by the aid of NIR, but also that it can be beneficial for the process cleanliness and improve the surface quality of built parts. Furthermore, a 430 stainless-steel (SS) component could be repaired by positioning it in a loose 316L SS powder bed using a fully NIR-heated PBF-EB process.

This study introduces an innovative approach for optimizing process development in electron beam powder bed fusion (PBF-EB) of non-flowing chemically reduced tungsten powder. Both line- and spot melting strategies were employed, with gradient-based variations of key processing parameters—beam current and scanning speed (line melting)/dwell time (spot melting)—applied across the XZ and XY planes on prismatic specimens. This method allowed mapping the transition from porous to swelling material within a single specimen and exposed the effects of changing gradient directions. Scripts were developed to analyze swelling and porosity from stacked backscattered electron data, providing valuable insights into material density and defect distribution. Optimal parameters for line melting (1400 W, 115 mm/s) and spot melting (1400 W, 4.5 ms dwell time) were identified, resulting in high-density samples. Solid samples were achieved with Archimedes densities of 99.8% and 99.9% respectively. Microscopical analysis verified parameter windows with dense, swelling-free material, selected for further builds and detailed characterization. Microstructural and compositional analysis was conducted using SEM and EBSD, while local micromechanical properties were assessed through micro hardness. Scaling up line melting was deemed infeasible due to warping, while spot melting was scaled to a melting area of 50 mm × 50 mm.