Enhancement of the compressive performances of additive manufactured Corrax maraging stainless steel lattice by heat treatment

The objective of this study was to investigate the influences of integrated solution and aging treatment (SAT) on the compressive properties of laser powder bed fusion (LPBF) Corrax maraging stainless steel lattices. Cubic and face-centered cubic with Z-axis strut (FCCZ) lattices were produced and used to formulate two types of functionally-graded material (FGM) lattices. The lattices with FGM directions parallel and vertical to the stress were designated as FGM-P and FGM-V lattices, respectively. The compressive performances and fracture mechanisms were identified experimentally by digital image correction and theoretically by finite element analysis. The results show that SAT can significantly increase the specific strengths of these lattices by 34-42 %. The compressive performances and fracture mode of the FGM-V sample principally corresponded to the rule of mixture. However, the FGM-P sample did not follow the rule of mixture because its deformation concentrated only in the cubic-dominated regions. Moreover, the SEAs of the cubic and FGM-P samples were respectively improved by 30 % and 19% by SAT, given their higher compressive strength and stable stress-strain curve. SAT can be applied to further extend the future application of these materials as cost-effective, high-performance lightweight structural materials.