Laser powder bed fusion (LPBF) is a promising technology to manufacture complex components. Aluminium (Al) alloys are extensively implemented in automotive and aerospace applications for their exceptional strength and stiffness to weight ratios. AlSi10Mg is a precipitation strengthened alloy. Due to the high cooling rate during the LPBF process, a fine microstructure in as-built samples is expected, increasing strength and hardness values. However, the ductility of as-built AlSi10Mg alloys is limited. Heat treatment allows control of microstructure influencing the mechanical properties and ductility. In this study, AlSi10Mg samples with a relative density >99.5% were manufactured with LPBF. Surface roughness values of 10.86 µm were achieved. Tensile and three-point bending samples were printed for analysis. Since load conditions of lattice structures in compression are much more complex compared to that of volume samples, increasing tensile ductility is not sufficient to determine the suitability of lattice structures for applications where high deformations are required. Therefore, lattice structures for compression testing were manufactured and individually heat treated to achieve a ductility of at least 20%. The precipitation size was found to increase depending on heat treatment from 0.44 µm up to 2.25 µm, giving insight on deformation behavior.

Metal powder bed-based Additive Manufacturing (AM) technologies, such as Electron Beam-Melting (EBM) and Laser Powder Bed Fusion (LPBF), are established in several industries due to the large design freedom and mechanical properties. While EBM and LPBF have similar operating steps, process-specific characteristics influence the component design. The differences in the energy coupling lead to differing solidification conditions, microstructures, and, thus, mechanical properties. The surface finish and geometrical accuracy are also affected. As opposed to LPBF, EBM powder layers are preheated prior to selective melting. In this study, similar volume energy densities in LPBF and EBM were used to manufacture Ti6Al4V test geometries to assess the process transferability. Since the energy coupling of LPBF and EBM differ, heat source absorption was considered when calculating the volume energy density. Even when a similar volume energy density was used, significant differences in the component quality were found in this study due to specific respective process constraints. The extent of these constrains was investigated on voluminous samples and support-free overhanging structures. Overhang angles up to 90° were manufactured with LPBF and EBM, and characterized with regard to the relative density, surface roughness, and geometric compliance.

Due to the increasing demand for electrification in the automotive sector, the interest in the manufacturing and processing of pure Copper (Cu; purity 99.99%) is also increasing. Laser-based technologies have proven to be challenging due to Cu’s high optical reflectivity. Processing pure Cu with Electron Beam Melting (EBM) is a promising manufacturing route, allowing for high design freedom. The highest priority is to achieve outstanding thermal and electric conductivity in manufactured Cu components. Chemical contamination or manufacturing defects, such as porosity, significantly reduce the thermal and electric conductivity. The literature on post-processing (thermal and abrasive) of additively manufactured Cu is scarce. Therefore, this study discusses the correlation between as built and heat treated microstructure, as well as surface roughness on the EBM electric conductivity. EBSD analysis is performed to analyze the effect of microstructure on electric conductivity. The effect of sandblasting and vibratory finishing on surface roughness and electric conductivity is investigated. Additionally, the samples are mechanically tested in terms of hardness.

High pressure die casting (HPDC) tools undergo several repairs during their life cycle. Traditional repair methods (e.g., welding) cannot always be applied on damaged tools, necessitating complete replacement. Usually, direct energy deposition (DED) is considered and applied to repair tools. In this study, the potential of laser powder bed fusion (LPBF) for HPDC tool repair is investigated. LPBF of the hot work tool steel 1.2343/H11 normally requires preheating temperatures above 200 °C to overcome cracking. Therefore, a process window for the crack-susceptible hot work tool steel 1.2343/H11 with no preheating was developed to avoid preheating an entire preform. Laser power, hatch distance, and scan speed are varied to maximize relative density. Since the correlation of LPBF process parameters and resulting build quality is not fully understood yet, the relationship between process parameters and surface roughness is statistically determined. The identification of suitable process parameters with no preheating allowed crack-free processing of 1.2343/H11 tool steel via LPBF in this study. The LPBF repair of a volume of ~2000 cm³ was successfully carried out and microstructurally and mechanically characterized. A special focus lays on the interface between the worn HPDC tool and additive reconstruction, since it must withstand the mechanical and thermal loads during the HPDC process.

Components manufactured with Metal Laser Powder Bed Fusion (PBF-LB/M) are built in a layerwise fashion. The PBF-LB/M build orientation affects grain morphology and orientation. Depending on the build orientation, microstructures from equiaxed to textured grains can develop. In the case of a textured microstructure, a clear anisotropy of the mechanical properties affecting short- and long-term mechanical properties can be observed, which must be considered in the component design. Within the scope of this study, the IN738LC tensile and creep properties of PBF-LB/M samples manufactured in 0° (perpendicular to build direction), 45° and 90° (parallel to build direction) build orientations were investigated. While the hot tensile results (at 850 °C) are as expected, where the tensile properties of the 45° build orientation lay between those of 0° and 90°, the creep results (performed at 850 °C and 200 MPa) of the 45° build orientation show the least time to rupture. This study discusses the microstructural reasoning behind the peculiar creep behavior of 45° oriented IN738LC samples and correlates the results to heat-treated microstructures and the solidification conditions of the PBF-LB/M process itself.

Metal laser powder bed fusion (PBF-LB/M) allows for high degrees of design freedom and the manufacture of high-temperature Ni-based materials, such as IN738LC. The PBF-LB/M microstructure is dependent on several factors, including process parameters, component geometry, build orientation and postprocessing steps (e.g., heat treatment). The correlation between the resulting microstructure and these parameters is material specific and not yet fully understood. In this study, the development of a specimen extraction cube (SEC), based on a generic component with design aspects related to turbomachinery applications, is presented. The SEC allows for the extraction of three samples, one for each of the build orientations: 0 deg (perpendicular to build direction), 45 deg (diagonal) and 90 deg (parallel to build direction). Specimens extracted from the SEC are mechanically tested and compared to witness samples manufactured in 0 deg, 45 deg, and 90 deg build orientation. Particular focus is placed on correlating measured properties and their variations with heat treated microstructures. Creep testing was performed using 240 MPa and a temperature of 850 °C. Microstructural differences and hence differences in mechanical properties are found in extracted and witness samples.