Structure-property relationship in high strength and lightweight AlSi10Mg microlattices fabricated by selective laser melting

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Aluminum alloy microlattices have been increasingly used in automotive, aerospace, packaging, defense, machinery, and construction industries due to their superior physical and mechanical properties such as high specific strength and energy absorption capacity. However, design and fabrication of microlattice structures remains a challenge because the structure-property relationship in aluminum microlattices has not been established. To address this issue, AlSi10Mg microlattices with different unit cell structures, number of unit cells, and strut diameters were designed and then fabricated by selective laser melting (SLM). The specific energy, compressive strength, and failure modes of the AlSi10Mg microlattices were examined. Experimental results have shown that the AlSi10Mg microlattices fabricated by SLM exhibited a maximum specific compressive strength of 83.113 MPa·g−1 cm3, which is higher than most metallic and non-metallic microlattices reported in the literature. During compression tests, four different failure modes, including contact region crushing, consecutive diagonal cracks at 45° to the loading direction, elastic/plastic buckling and plastic deformation, and single diagonal crack at 45° to the loading direction, were observed. In addition, the microlattices with different unit cells exhibited different strength-density relationships due to these different failure modes.