A Janus-Like Bio-Inspired Strategy for 3D-Printed Bimetallic Metamaterials with Excellent Thermal-Protection and Load Bearing Capacity.

Abstract

Functional structures that combine thermal protection with load-bearing capabilities represent an effective solution to hypersonic thermal-protection challenges. Here, we propose a Janus-like bio-inspired strategy for integrally 3D-printed bimetallic metamaterials. Inspired by shell bilayers, a heat-resistant AlSiFeMnNiMg alloy and a SiC-reinforced AlSi10Mg are arranged as an architected pair and fabricated via dual-hopper selective laser melting, with SiC volume fractions of 0, 4, and 8 vol%. In situ SEM tensile tests at 25°C and 250°C show that damage is confined to a narrow transition zone. Once one side softens, the bimetallic architecture redirects load to the other, forming non-percolating high-stress paths and stabilizing the plateau response. Quasi-static compression of Gyroid TPMS lattices with different SiC contents maps the composition-temperature space. Across temperatures, structures with 4 vol% SiC improve specific energy absorption by 11.72% and 18.67% in room temperature and by 10.28% and 18.8% in 250°C, achieving synergistic mechanical improvement and a stable energy-absorbing plateau under extreme environments. Relative to 0 and 8 vol%, where modulus mismatch precipitates premature localized collapse, 4 vol% SiC promotes a distributed shear-band network that delays failure and elevates load capacity. This work provides a practical pathway toward thermally protective and load-bearing integrated components for aerospace applications.