# The Effects of Unit Cell Arrangement and Hybrid Design on the Compressive Performances of Additive Manufactured Corrax Maraging Stainless Steel Lattices

## TL;DR

This study shows how combining different unit cell designs in 3D-printed metal lattices improves their strength and energy absorption under compression.

## Contribution

The paper introduces a hybrid lattice design that optimizes both unit cell geometry and arrangement for enhanced compressive performance.

## Key findings

- The hybrid lattice achieved the highest compressive strength and energy absorption compared to other designs.
- It outperformed other lattices in specific energy absorption by 21.76% and 8.07%.
- Uniform stress distribution and delayed shear banding explain the improved performance.

## Abstract

Selective laser melting (SLM) enables the production of complexly shaped metals with programmable mechanical responses, yet most lattice studies still rely on a single unit cell and a simple columnar build, severely restricting performance improvements. Here, we examine how combining distinct unit cells and rearranging them within the build volume affects the compressive behavior of SLM Corrax maraging stainless steel lattice structures. Three designs are additively manufactured as follows: a columnar cubic-FCCZ lattice, an alternating cubic and FCCZ lattice, and a hybrid lattice (cubic+FCCZ unit cell). In situ 2D digital image correlation (DIC) and finite element analysis (FEA) are used to resolve full-field strain evolution and failure modes under quasi-static compression. The hybrid lattice achieves the highest first maximum compressive strength (418 ± 5.78 MPa) and energy absorption (128.5 ± 6.83 MJ/m3), with its specific energy absorption (44.2 ± 1.48 kJ/kg) outperforming that of the columnar cubic-FCCZ lattice and alternating cubic and FCCZ lattice by 21.76% and 8.07%, respectively. The enhanced performance is attributed to the more uniform stress distribution and delayed shear band localization afforded by the hybrid lattice. These findings show that simultaneously optimizing unit cell geometry and arrangement can significantly expand the design space of metal lattices and provide a practical approach to improving the compressive strength and energy absorption capacity of load-bearing SLM components.