Triply‐Twinned Metamaterials: Unraveling the Mechanics and Failure Pathways Through High‐Resolution XCT

Abstract

ABSTRACT We designed and engineered a novel class of triply‐twinned Body‐Centred Cubic (BCCT) lattices that achieved up to three‐fold improvements in mechanical performance over conventional BCC lattice architecture. Inefficient strut deformation and defect‐sensitive failure limit the performance and reliability of architected metamaterials. Triply‐twinned meta‐crystal architectures transform the dominant strut‐scale deformation from bending to stretching in both polymeric (Rigid 4K) and metallic (Ti‐6Al‐4V) Additively Manufactured (AM) BCCT lattices, significantly enhancing their stiffness (+380%) and strength (+279%). Using high‐resolution synchrotron X‐ray computed tomography, image‐based finite element models, scanning electron microscopy, and pyrometry, we correlate fracture mechanisms to the architecture design and as‐built defects in these AM lattices. We further reduce defect‐driven fracture by 50% without altering the global failure mode by adjusting the build orientation of the lattices. This integrated, multi‐scale approach links fundamental deformation mechanics to manufacturability, providing a broadly applicable design strategy for next‐generation architected metamaterials with exceptional performance and reliability.