Integrated metal MEX manufacturing of bimetallic TPMS-core sandwich panels for lightweight structural applications

Multi-material metal additive manufacturing (AM) enables the integration of dissimilar alloys within a single component; however, fully integrated bimetallic sandwich panels remain largely unexplored. This work presents a one-step AM strategy for fabricating bimetallic sandwich panels with bio-inspired cellular cores, combined with a full-geometry finite element (FE) model for predicting flexural behavior. The panels were manufactured without secondary joining, achieving continuous material transitions and effective interfacial bonding. Three-point bending tests were performed to evaluate stiffness, strength, and failure mechanisms, validating the FE model and capturing the effects of material heterogeneity and architectural features beyond homogenized approaches. The manufactured panels exhibited flexural modulus values of 29.98–150.45 GPa and flexural strength values of 200.44–769.12 MPa, with densities ranging from 1740 to 6384 kg/m³. Flexural performance reached up to approximately twice that of single- and hybrid-manufactured reference structures. These results demonstrate the feasibility of fully additive fabrication of structurally functional bimetallic sandwich panels and provide a validated framework linking process, architecture, and mechanical response.