Robust and resilient Mg–NiTi interpenetrating-phase composites with triply periodic minimal surface configuration

Abstract

Magnesium (Mg)-based materials are promising for lightweight structural applications. However, their widespread adoption is significantly constrained by inherent limitations in mechanical properties. To address this challenge, this study introduces a novel Mg-based interpenetrating-phase composite reinforced with a nickel-titanium (NiTi) scaffold featuring a triply periodic minimal surface (TPMS) configuration. By combining experimental investigations with finite element simulations, we systematically elucidate the dual impact of the scaffold's unit cell size (a) on manufacturing viability and mechanical enhancement. To compensate for compromised infiltration dynamics induced by decreasing a, a critical permeability threshold of 1 × 10⁻⁸ m² is proposed for achieving successful composite fabrication. Mechanically, reducing a strengthens the interaction between the scaffold and matrix: the TPMS-configured NiTi scaffolds improve stress transfer, deflect crack propagation, and facilitate damage localization, whereas the Mg matrix preserves structural integrity and enables load redistribution. Consequently, the composites significantly outperform pure Mg, and lowering a leads to more substantial enhancements in compressive strength, energy dissipation, and deformation recoverability. This study offers valuable insight into the design and fabrication of high-performance Mg-based materials for structural and biomedical applications.