# Compressive Behavior of Inconel 625 and Ti-6 Al-4V Strut Lattices Fabricated by LPBF
###### Abstract
To further the understanding of lattice structures, this study evaluated the compressive behavior of four SLM-produced Inconel 625 and Ti-6 Al-4V lattice architectures. It is noteworthy that the available literature on the mechanical properties of Inconel 625 lattice structures is relatively limited. The goal of the present study was to evaluate the behavior of four lattice structures manufactured by LPBF from two high-performance alloys, which are used especially in the  
Figure 1: Examples of 3D lattice structures using different cell designs arranged over a cubic volume (designed using nTop software, version 4.9). aerospace field, under compressive loads. This study was justified because the scientific community has registered a great interest in such studies. The computation analysis consisted of performing a static finite element analysis with nTop, dedicated software package for lattice development [34], and topology optimization of parts for additive manufacturing. Finite element analysis (FEA) software packages, such as ANSYS [34; 35], MSC Mark [36], and ABAQUS [17], are typically employed to customize numerical models for simulation and generate stress-strain curves. In a previous study published by the authors [37], it was concluded that the mechanical performance of lattices under flexural loads can be assessed by performing a simplified static finite element analysis in nTop. The same cell types and materials were used during the present study. This study combines experimental and simplified computational approaches to evaluate the compression performance of four advanced lattice structures--octet cell, truncated octahedron cell, Kelvin cell, and re-entrant cell, which are not so common in the available literature--manufactured using the LPBF method from Inconel 625 and Ti-6 Al-4V, showcasing the versatility of these materials in lattice design and their implications for mechanical performance. By leveraging cutting-edge nTop software for precise lattice design and employing static finite element analysis for mechanical performance assessment, this research provides comprehensive insights into the interplay between material selection, lattice geometry, and compression behavior. It is worth mentioning that for this study, conformal patterning was applied to design cylindrical compression test specimens because the studied lattices are to be integrated in the future into the cylindrical internal passages of propulsion system components (cooling channels), which is considered a novelty. The conformal patterning approach is suitable for cases where the lattice must adapt to non-planar surfaces, integrating the lattice into the part's geometry. The proposed design can improve the load distribution in different areas, enhance functionality, and maximize the fluid flow for heat dissipation. In addition, conformal patterns are a design option enabling engineers to benefit from the advantages of AM. It is worth highlighting that most existing studies on the compressive properties of lattices assess these properties based on cubic or rectangular specimens. These findings hold significant potential for optimizing lightweight, high-strength components for applications in the aerospace, automotive, and biomedical sectors.