The world of materials science has reached a turning point with the advent of a 3D printed titanium metamaterial displaying levels of strength unattainable in natural or traditional manufactured materials. This metamaterial has a unique and intricate lattice structure that reportedly renders it 50% stronger than the next strongest alloy with similar density, making it a promising candidate for applications ranging from medical implants to aerospace and rocket parts.
The metamaterial owes its supernatural strength to the pioneering work of researchers from RMIT University in Australia, who have taken cues from nature’s own blueprint. Lattice structures with hollow struts have long been inspired by strong, hollow-stemmed plants such as the Victoria water lily. However, the journey to replicate these structures in metals has been plagued by manufacturability issues and stress concentration inside the hollow struts, which often led to premature failures. RMIT’s Distinguished Professor Ma Qian pointed out that traditionally, “less than half of the material” would bear most of the compressive load, leaving a substantial volume structurally insignificant.
Through the use of metal 3D printing, the RMIT team has circumvented these issues by optimizing a lattice design that spreads stress more uniformly, thereby boosting the material’s structural efficiency. According to the team, “We designed a hollow tubular lattice structure that has a thin band running inside it.” This innovative configuration melds two complementary lattice structures to mitigate the weak points where stress typically accumulates.
The titanium-alloy metamaterial developed by the RMIT researchers not only surpasses the strength of cast magnesium alloy WE54, commonly used in aerospace, but also showcases impressive structural integrity when loaded along various axes. The team utilized computer-aided design (CAD) software to merge the designs and employed laser powder bed fusion (LPBF) to print the material. The professor elaborated on their approach, stating, “We chose to do this manually instead of programmatically to highlight that the design of these advanced metamaterials is highly accessible.”
The researchers have successfully fabricated multi-topology Ti-6Al-4V TP-HSL specimens with compressive yield strengths of up to 263MPa and ultimate compressive strengths reaching 376MPa, alongside elastic moduli up to 11GPa. The brilliance of their design is the halving of stress concentration on the lattice’s most vulnerable points, and an ingenious double lattice design that directs cracks along the structure, amplifying the toughness.
The adaptability of this metamaterial is one of its most compelling advantages. According to PhD candidate Jordan Noronha, the structure can be printed “at several millimeters and up to several meters using different printers.” The broad applicability, ranging from biocompatibility for bone implants to corrosion and heat resistance suitable for rocket components, speaks volumes about the potential of this technology. LPBF’s ability to produce high-resolution sub-millimeter scale features furthers this material’s suitability for advanced applications.
Qian and his team are optimistic about the future of this technology, despite its current exclusivity. They are steadfast in their commitment to refining the material for even greater efficiency and exploring its high-temperature applications. The group’s vision is to make these advanced metamaterials more widely accessible, revolutionizing traditional manufacturing constraints and unleashing new possibilities across various industries.
Relevant articles:
– 3D printed titanium structure shows supernatural strength – A 3D printed ‘metamaterial’ boasting levels of strength for weight not normally seen in nature or manufacturing could change how we make everything from medical implants to aircraft or rocket parts.
– 3D-printed titanium metamaterial boasts ‘supernatural’ strength, IOM3, Wed, 10 Apr 2024 10:13:10 GMT
– Microprinting millions of microparticles in the blink of an eye through multi-photon 3D laser printing, Phys.org, Mon, 08 Apr 2024 21:06:18 GMT