Three-dimensional assembled dual-material lattice with tailorable thermal expansion: Design method, modeling, and testing

The lightweight dual-material metal lattice structure with the tailorable coefficient of thermal expansion (CTE) has attracted increasing attention for aerospace applications. However, previous work on these metal structures was mainly directed to theoretical design with the limited experimental demonstration in planar geometries because it is challenging to fabricate three-dimensional (3D) metal lattices with highly complex geometric connections. In this article, we propose a node assembly dual-material lattice design method enabling the experimentally demonstrated 3D designs with the tailorable CTE. A theoretical model of the thermal expansion and mechanical properties is provided to link the thermo-mechanical properties to the configuration and base materials. Based on the proposed design method and the theoretical model, we present three geometrical layouts with experimentally demonstrated CTEs of 34.77ppm/°C, -16.21ppm/°C, and 0.05ppm/°C, respectively. Notably, the achieved CTE of 0.05ppm/°C has never been reported in previous studies. In addition, the proposed assembled lattice can be extended periodically. Based on the demonstrations, we expect that the proposed method is promising for structurally efficient lattices design with high dimensional stability in aerospace engineering.