Characterization and analysis of quasi-static mechanical properties of large-scale stainless steel BCC lattice structures fabricated by Wire Arc Additive Manufacturing

Thanks to the thriving development of additive manufacturing, the widespread industrial application of lattice structures has become a reality. However, the current scarcity of research on the quasi-static compression behavior of large-scale body-centered cubic (BCC) unit cell lattice structures has, to some extent, hindered their engineering applications. This paper first explored the failure modes of single-unit-cell and multilayer BCC lattice structures fabricated using the Wire Arc Additive Manufacturing (WAAM) method under quasi-static compression. Subsequently, the tensile properties of the rods and nodes within the structures were investigated, analyzing the impact of heat dissipation efficiency on these properties. Finally, a microstructural analysis of the sampled locations was conducted. Experiments reveal that the ultimate compressive loads for single-unit-cell and multilayer BCC structures were 23.57 kN and 50.51 kN. The tensile strength at the node positions was 3.89 % higher than that at the rod positions, accompanied by smaller grain sizes and smaller grain boundary misorientations at the nodes. The WAAM technology employed in this research allowed for the production of more rationally designed large-scale BCC multi-unit lattice structures. By reinforcing the stress-concentrated areas such as nodes, failure was mitigated from occurring at points susceptible to instability. This achievement had facilitated the application of large-scale BCC lattice structures in engineering to a certain extent.