Effect of topology on the mechanical properties and energy absorption of annealed lightweight SLM AlSi10Mg lattice structures

Additively manufactured lattice structures have gained significant attention from various industries due to their exceptional specific mechanical properties and low bulk densities. While research on the performance of lattice structures made of 316L stainless steel and Ti-6Al-4V has been extensive, the performance of AlSi10Mg lattices remains relatively unexplored, despite their low density. This work investigates the mechanical properties and energy absorption capabilities of AlSi10Mg strut-based and Triply Periodic Minimal Surface (TPMS)-based lattice structures with different topologies. Specifically, the study included 9 lattice geometries: strut-based designs such as Body-Centered Cubic (BCC), BCC with Z-struts (BCCZ), and Rhombic Dodecahedron (RD); as well as TPMS-solid and TPMS-sheet structures of I-graph-wrapped package (IWP), Diamond, and Gyroid. First, the alloy's microstructure was examined, and then the stress-strain curves and deformation modes of the lattice structures were analyzed. Regression models were derived from the experimental data to predict the first peak stress, elastic modulus, and energy absorption of lattice structures. Finally, the absolute and specific properties of AlSi10Mg lattices were compared with each other and with lattices made of different alloys from the literature. The results showed that TPMS-sheet lattice structures have the highest absolute and specific properties. TPMS-sheet Diamond lattice structures with a 0.2 relative density have an elastic modulus of 603.6 MPa, a first peak stress of 37.15 MPa, and a volumetric energy absorption of 21.44 MJ/m 3 . They deformed in a stretch-dominated behavior. BCCZ lattice structures had comparable mechanical properties, but their energy absorption was hindered by the buckling of the vertical struts and subsequent catastrophic failure of the lattice. • Sheet TPMS lattices exhibited the highest absolute and specific mechanical properties, as well as energy absorption, compared to strut-based and solid TPMS structures. • Strut-based BCCZ lattices achieved specific mechanical properties comparable to sheet TPMS structures, but their energy absorption was limited due to brittleness. • AlSi10Mg lattices have specific strength equal to or exceeding steels, but lower than Ti-alloy lattices.