3D desktop prints 4D multi-metal objects
4D printing can now create complex 3D geometries that react to environmental stimuli, opening new design opportunities in materials science. A vast majority of 4D printing approaches use polymer materials, which limit the operational temperature during the process of engineering. In a recent study, Xiaolong Chen and co-workers at Dyson School of Design and Engineering, Department of Earth Science and Engineering and Department of Materials at Imperial College of London, UK, have developed a new multi-metal electrochemical 3D printer. The device can construct bimetallic geometries by selectively depositing different metals with temperature-responsive behaviour programmed into the printed structure.
In the study, scientists demonstrated a meniscus confined electrochemical 3D printing approach using a multi-print head design and nickel and copper materials as examples—the ability can be transferred to other deposition solutions.

Additive manufacturing, popularly known as 3D printing, can fabricate complex 3D architectures by sequentially joining materials layer-by-layer. Flexibility of this technique has found applications in aerospace, automotive, medical and energy industries. At first, applications of additive manufacturing focused on the use of polymers to ease consolidation, either via photo-polymerisation (stereolithography) or thermal processes (such as fused deposition modelling). However, increased uptake of metal-based additive manufacturing has now transitioned the technology from a prototyping tool to engineering end products.
Illustration of low-cost electrochemical multi-metal 3D printer—front view (a), print head setup (b) and detailed view highlighting deposition nozzles and deposited bimetallic strip (c) (Credit: Scientific Reports)