Neutron-star-inspired metamaterials: mitigating friction-strength-conductivity trade-offs.

Modern technological demands require metals to integrate structural and functional performance, yet conventional metallurgy remains constrained by intrinsic trade-offs among strength, electrical conductivity, and wear resistance. Neutron-star evolution offers a natural blueprint for overcoming this limitation: load-bearing nuclear matter forms continuous frameworks, while a permeating electron sea enables efficient charge transport, intrinsically decoupling mechanical support from transport functionality. Inspired by this principle, we designed a neutron-star-inspired metallic metamaterial that assigns load bearing to a tungsten framework and electrical transport to a silver network. Realized through sequential 3D printing and metal infiltration, the resulting Ag-W architecture delivers high strength (≈213 MPa), high electrical conductivity (>50% IACS), and ultra-low friction-reduced to ∼20% of conventional bulk metals, demonstrating an unusually favorable convergence of mechanical, electrical, and tribological performance that is difficult to achieve through composition-based alloying alone. Crucially, the performance gain goes beyond a simple composite effect, as evidenced by the ∼75% reduction in friction relative to non-neutron-star-like architected comparators. These results establish topology-guided metallic architectures as a promising complementary route for mitigating multi-property trade-offs.