Strut and sheet metal lattices produced via AM-assisted casting and powder bed fusion: A comparative study

Abstract

The current work analyzes the process-microstructure-mechanical property relationship of metallic lattices manufactured through additive manufacturing (AM)-assisted investment casting and powder bed fusion (PBF) techniques. For the analysis, both solid- and sheet-network-based gyroid lattices are manufactured using AlSi10Mg alloy as base material. Micro-tomography and scanning electron microscopy are employed to assess the differences in the as-built structure quality in each design case, identifying method caveats and quantifying differences in the distribution and magnitude of the lattice's inner porosity. Moreover, their nonlinear compressive mechanical performance is experimentally probed to assess the elastic stiffness, peak, plateau stress, as well as overall energy absorption in each case. Results indicate higher elastic stiffness and peak stress for the PBF-manufactured specimens irrespective of the lattice topology and overall comparable stress and energy absorption properties. However, in contrast to PBF specimens, AM-assisted lattices exhibit a low-stress variability throughout the plateau region, yielding an overall smooth post-elastic stress-strain response, a difference that is particularly prominent for the solid-network type lattice architectures.

Keywords

• Metallic lattices
• Additive manufacturing assisted casting
• Powder bed fusion
• Metamaterials
• Investment casting