Investigation of process parameters' effects on the mechanical behavior of lattice structures produced by selective laser melting under quasi-static loading

Lattice structures have gained significant importance in engineering applications due to their superior properties, such as lightness and strength. These structures are commonly used in critical functions like load-bearing, energy absorption, and thermal management in aerospace, automotive, and biomedical sectors. With advancements in additive manufacturing technologies, they can now be produced in more complex and optimized geometries. In this context, selective laser melting (SLM) is one of the most suitable technologies for producing complex lattice structures with high precision. In this thesis, the mechanical performance of two different lattice geometries, namely face and body-centered cubic with vertical struts (FBCCZ) and diamond, was investigated. The FBCCZ lattice geometry enhances load distribution by placing primary load-bearing beams on the cell faces and center, providing high stability under compression. The vertical struts increase axial compressive strength, improve stiffness in the direction of deformation, and offer efficient energy distribution, making them advantageous for applications requiring impact resistance. Additionally, minimal material usage makes the FBCCZ geometry lightweight and durable. On the other hand, the diamond lattice geometry strikes a balance between lightness and high strength, offering multi-directional strength and resistance to various load types. Due to its energy distribution and absorption capability, it is ideal for applications requiring impact resistance. In this study, experimental specimens were produced using the selective laser melting method with AlSi10Mg powders. The effects of process parameters such as scanning speed, layer thickness, and hatch spacing on the compressive strength and energy absorption levels of the lattice structures were examined. Test results showed that an increase in scanning speed reduced the maximum compressive force in FBCCZ lattice structures but increased it in diamond lattice structures. An increase in layer thickness generally decreased the maximum compressive force. While an increase in scanning speed had minimal effect on energy absorption, increases in layer thickness and hatch spacing typically reduced energy absorption. In FBCCZ structures, an increase in hatch spacing initially increased the compressive force, followed by a decreasing trend, whereas the opposite trend was observed in diamond structures. Overall, it was concluded that manufacturing parameters and lattice geometry have a significant impact on mechanical performance, though these effects vary depending on the specific geometry. Keywords: Additive manufacturing, Selective laser melting, Quasi-static compression, Lattice structures, Energy absorption, Process parameters