Triply-twinned architected lattices are engineered materials made of repeating 3D structures arranged in a precise pattern. ‘Triply-twinned’ refers to three reflection planes in each unit about which sub-structures are mirrored, giving the structure extra strength under compression. In general, they are made from polymers or metals, depending on the application.

Currently, scientists are exploring them for potential applications where low weight is critical, such as in aerospace, energy and advanced engineering. However, they are not yet common in commercial products, with the main limitation being the manufacturing process.

“We are excited to translate the concept of twinning, normally observed at the atomic scale, into centimetre‑scale architected materials using additive manufacturing. This approach allows us to precisely tailor stiffness, strength, and damage tolerance, opening new opportunities for applications ranging from biomedical implants and heat exchangers to energy‑absorbing components,” says Chu Lun Alex Leung, professor at University College London (UCL) and corresponding author of the publication.

Through the EPSRC International Centre to Centre collaboration: Manufacturing by Design, Leung (work package lead) and his team from UCL, together with scientists at the University of Sheffield and the ESRF have designed, engineered, characterised, and analysed a series of additively manufactured lattices that have shown a successful increase in the stiffness (+380%) and strength (+279%) of materials.

The team used different tools to analyze the effect of the lattice structure, defects and mechanical strength of the printed material. They came to the ESRF to use high‐resolution synchrotron X‐ray computed tomography on beamline BM18. “We characterized the fracture dynamics by applying sequential compressive stress. With high resolution 3D synchrotron images, we could precisely localize the micro-defects and their effect on structural integrity of the lattice.” explains Jaianth Vijayakumar, scientist at the ESRF and part of the team. In additive manufacturing of metals, defects are manifested in micro size pores, high energy X-ray photons at BM18 provide the necessary transmission and noise free reconstruction, making an important tool in this project. “The performance of additively manufactured lattices depends on how architecture and defects interact during deformation. Synchrotron XCT allows us to directly observe these features and connect them to how and where failure occurs.”

Cutting defects by 50%

The data from the ESRF, combined with image‐based finite element models, scanning electron microscopy and pyrometry, showed why and how the 3D-printed lattices break because of the design of the structure itself or because of the imperfections that occur during 3D printing.

“We found that by changing the orientation of the part during the printing process, we could cut defect-related failures in half”, explains David McArthur, first author of the publication.

This multi-scale approach, which combines characterisation of the deformation of materials plus how the manufacturing introduces defects, provides researchers with a roadmap to design advanced materials that are strong and reliable in theory but also in practice.

Reference

D.McArthur, et al. “Triply-Twinned Metamaterials: Unraveling the Mechanics and Failure Pathways Through High-Resolution XCT.” Advanced Materials (2026): e16173. https://doi.org/10.1002/adma.202516173

Text by Montserrat Capellas Espuny