The Impact of Size and Loading Direction on the Strength of Architected Lattice Materials

Lattice materials are strong yet light. Miniaturizing the pattern size to the micro-scale allows exploiting mechanical size effects. So far, the impact of the lattice size on the strength has not been studied systematically and mechanical characterization has been focused on compression tests only. Here, the strength of polymer-alumina core-shell composite microlattices with different pattern sizes is investigated in compression and tension. The compressive strength increases by a factor of two when the lattice size is scaled down by 50%. With tensile strengths of up to 27 MPa at 0.37 g cm(-3), the microlattices outperform all technical foams and most monolithic ceramics. Isotropic strength under tension and compression is found when thickness-dependent notch effects in the alumina shells are considered.