  Additive Manufacturing (AM) has enabled the fabrication of metallic cellular
materials that are of interest in the design of lightweight impact resistant
structures. However, there is a need to understand the interactions between:
(i) the material architecture, (ii) the AM process parameters, and (iii) the
as-built geometry, microstructure and energy absorbing properties. In this
work, we investigate the quasi-static and dynamic behaviour of cellular
materials manufactured from 316L stainless steel using laser powder bed fusion
(LPBF). Four cellular architectures are considered (octet lattice,
lattice-walled square honeycomb, origami and square honeycomb), as well as
three sets of AM process parameters, characterised by laser powers of 50, 125
and 200 W. The exposure time is adjusted to deliver the same total heat input.
The 125 W case leads to material with the highest strength and ductility. The
cellular materials with this process variant match their nominal densities most
closely, and have the highest strength and energy absorption. Either reducing
(50 W) or increasing (200 W) the power leads to a significant increase in
porosity, reducing strength and energy absorption. However, we find that
changes due to process-induced porosity have a smaller influence than those
resulting from the choice of cellular architecture.
