High energy absorption and deformation recovery of laser powder bed fused NiTi arched spiral lattices via hybrid structural design

• The arch − spiral lattice structure developed through a hybrid structural design strategy. • A hybrid structural design incorporating spiral features can effectively mitigate stress concentration. • Hybrid structural design can enhance the mechanical and functional performance of structures. In conventional NiTi alloy lattice structures, stress concentrations at the nodes during deformation frequently lead to localised deformation zones, surpassing the reversible strain limits and diminishing energy absorption capacity. To address this issue, this study introduces a novel Arch-shaped Spiral Lattice Structure (ASLS), fabricated via laser powder bed fusion (LPBF). This structure integrates spiral features with conventional Arch-shaped Lattice Structures (ALS) through a hybrid design strategy to mitigate stress concentrations. Finite element analysis indicates that the spiral feature effectively reduces stress concentration in the ALS and enhances its damage tolerance. Mechanical testing reveals that the ASLS achieves an energy absorption of 241.32 J and a specific energy of 16.62 J/g, representing improvements of 297.89 % and 166.35 %, respectively, over the ALS. Shape memory effect tests demonstrate that the ASLS exhibits only 0.449 % cumulative irreversible strain after 10 compression-thermal cycles, highlighting superior shape memory stability. This enhancement is attributed to the continuous geometric characteristics of the spiral structure, which enable coupled torsional and bending deformation. This work provides valuable insights into the development of high-performance, reusable NiTi lattice structures, broadening their applications in aerospace buffering, biomedical scaffolds, and other advanced engineering domains.