New 3D Printed Metamaterial Could Revolutionize Aircraft and Rocket Parts Production

Repeatedly, researchers draw inspiration from nature to drive innovation. Recently, we highlighted the development of a novel 3D printing technique by researchers inspired by chameleons. Similarly, the Fraunhofer Institute is exploring insect-inspired wood binders for 3D printing. In the most recent breakthrough, scientists at RMIT University have engineered a metamaterial using 3D printing, featuring a lattice structure of hollow struts reminiscent of the resilience found in organ pipe corals (Tubipora musica) or the hollow stems of the Victoria water lily. This new material could impact aircraft or rocket parts production, for example.

The 3D printed metamaterial was produced at the RMIT Advanced Manufacturing Precinct using the Laser Powder Bed Fusion (LPBF) 3D printing process from a titanium alloy, which in itself is not a novelty. The material’s novelty and nomenclature stem from its artificial composition, possessing distinct properties absent in natural counterparts. Resembling a 3D printed titanium lattice cube, this metamaterial boasts a remarkable strength-to-weight ratio unprecedented in natural materials, seamlessly merging lightweight attributes with exceptional strength. The developed metamaterial’s lattice structure is notable: it is 50% stronger than the next most durable material, the cast magnesium alloy WE54. WE54 shares a similar density and is often used in the aerospace industry.

Stress concentrations in red and yellow on the grid (left), while (right) the new grid structure distributes the stress more evenly.

With this design, the lattice structure effectively distributes stress, reducing vulnerabilities by half and deflecting potential cracks along its framework. This result yields a significantly more resilient structure, poised for application in aerospace manufacturing for aircraft or rocket components and in medical devices like bone implants. The material’s biocompatibility, corrosion and heat resistance further underscore its potential versatility.

The Path to a More Stable Material

According to RMIT professor Ma Qian, in the past, decades of attempts to replicate the hollow “cellular structures” in metals have failed due to problems with manufacturability and the concentration of stress on the inner areas of the hollow struts, which has led to premature failures. Detailing this process, Qian explained: “Ideally, the stress in all complex cellular materials should be evenly spread. However, for most topologies, it is common for less than half of the material to mainly bear the compressive load, while the volume of material is structurally insignificant.”