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.

Additive manufacturing (AM) is a key technology for the individualized and resource-efficient production of structural components. Recent developments in manufacturing technologies enable improved quality of additively manufactured components and therefore they become more and more important in lightweight constructions. An example is the substitution of solid material by porous lattice structures. Those embedded lattice structures lead to highly weight-efficient structures. Most recent investigations focus on numerical and experimental studies to describe the mechanical behavior of lattice structures. In this paper, a method to determine analytical expressions for the axial stiffness properties of lattice structures is presented. The displacement method and direct stiffness method are used to derive symbolic parameter-dependent formulas for the axial stiffnesses and effective Young’s moduli for f₂cc,z, and bcc unit cells. Furthermore, an empirical approach based on Finite Element simulations is presented to describe the stiffness reduction for non-embedded or rather free lattice structures. The results are further validated by physical experiments. Stereolithography is used for specimen production. f₂cc,z, and bcc lattice structures are embedded in thin-walled rectangular aluminum tubes and tested under compression load. Furthermore, lattices without a surrounding tube are tested. The analytical and empirical solutions are in good agreement with the experimental and numerical results.

Sandwich structures possess a high bending stiffness compared to monolithic structures with a similar weight. This makes them very suitable for lightweight applications, where high stiffness to weight ratios are needed. Most common manufacturing methods of sandwich structures involve adhesive bonding of the core material with the sheets. However, adhesive bonding is prone to delamination, a failure mode that is often difficult to detect. This paper presents the results of delamination testing of fully additive manufactured (AM) AlSi10Mg sandwich structures with pyramidal lattice truss core using Laser Powder Bed Fusion (LPBF). The faces and struts are 0.5 mm thick, while the core is 2 mm thick. The inclination of the struts is 45°. To characterise the bonding strength, climbing drum peel tests and out-of-plane tensile tests are performed. Analytical formulas are derived to predict the expected failure loads and modes. The analytics and tests are supported by finite element (FE) calculations. From the analytic approach, design guidelines to avoid delamination in AM sandwich structures are derived. The study presents a critical face sheet thickness to strut diameter ratio for which the structure can delaminate. This ratio is mainly influenced by the inclination of the struts. The peel tests resulted in face yielding, which can also be inferred from the analytics and numerics. The out-of-plane tensile tests didn’t damage the structure.

For orthopaedic applications, additive manufactured (AM) porous scaffolds made of absorbable metals such as magnesium, zinc or iron are of particular interest. They do not only offer the potential to design and fabricate bio-mimetic or rather bone-equivalent mechanical properties, they also do not need to be removed in further surgery. Located in a physiological environment, scaffolds made of absorbable metals show a decreasing Young’s modulus over time, due to product dissolution. For magnesium-based scaffolds during the first days an increase of the smeared Young’s modulus can be observed, which is mainly attributed to a forming substrate layer of degradation products on the strut surfaces. In this study, the influence of degradation products on the stiffness properties of metallic scaffolds is investigated. For this, analytical calculations and finite-element simulations are performed to study the influence of the substrate layer thickness and Young’s modulus for single struts and for a new scaffold geometry with adapted polar cubic face-centered unit cells with vertical struts (f2cc,z). The finite-element model is further validated by compression tests on AM scaffolds made from Zn1Mg (1 wt% Mg). The results show that even low thicknesses and Young’s moduli of the substrate layer significantly increases the smeared Young’s modulus under axial compression.

The present research is focusing on the better understanding of the behaviour of the re‐entrant auxetic structures subjected to impact loads. Various results like the energy absorption capacity, impact force and force‐displacement curves are predicted by performing numerical simulations in ABAQUS. Furthermore, some comparative studies have been performed on different parameters associated with the geometry and the impactor mass to gain a better understanding of re‐entrant auxetic structures on its performance under the impact, mainly focusing on energy absorption characteristics.