Compressive deformation behavior of functionally graded lattice structures of stainless steel 316L

In this study, uniform lattice structures with four different relative densities (RD) and corresponding graded porous lattice structures of body-centered cubic, face-centered cubic and gyroid have been designed and successfully fabricated through laser powder bed fusion technique. Fabricated lattice structures of stainless steel 316L have been subjected to microscopical analysis to reveal the quality of the prepared lattice structures. Considerable amount of deviation in the dimensions of printed lattice struts was observed, this also affects the porosity fraction of the prepared lattice structures. All the prepared lattice structures (uniform and graded) were tested under compression at strain rates of 0.01, 0.1 and 1 s⁻¹. Furthermore, the effect of strain rate, geometry and RD on deformation behavior of graded and uniform lattice structures was investigated. The result shows that regardless the geometry and RD, with the increase in compressive strain rate, the yield strength of the lattice structures increases. Also, it is observed that the graded lattice structures show superior energy absorption capacity and mechanical properties as compared to the uniform lattice structures. The results of this study offer valuable insights into the design and fabrication of functionally graded porous lattice structures, particularly for applications requiring high compression performance.