Lecture
Influence of the miniaturization effect on lattice structures by means of PBF with AlSi10Mg
Powder bed fusion (PBF) enables the manufacturing of cellular structures that have a high lightweight potential due to their advantageous stiffness to weight ratio, such as honeycombs or lattice structures. However, the manufacturing process impacts heavily the mechanical performance of such structures so that their reliability and reproductivity cannot be achieved by simple general design rules and corresponding justification methods which hinders their implementation in lightweight load carrying structures
Apart from increased porosity and deviating strut geometry, one typical process induced imperfection of thin walled structures by PBF is the so called miniaturization effect, which is a textural arrangement of the strut microstructure due to local temperature gradients that depends on the process parameters, material type and structure type and feature dimensions. This very specific effect leads to reduced stiffness and strength and, thus, significantly influences the elasto-plastic properties of lightweight-relevant structures.
This contribution aims at the quantification of the drivers of the miniaturization effect by vertical lattice struts. Tensile test are conducted for single strut specimens manufactured by means of PBF with AlSi10Mg in order to identify a correlation of the mechanical properties with surface roughness, dimensional accuracy, porosity and microstructure for identified process parameters. A basic understanding of these dependencies will lead to reliable manufacturing and better predictive models allowing exploitation of the lightweight potential of lattice structures for industrial purposes.
