Manufacturing News, Research and Development, Victoria

RMIT 3D prints titanium structure showing supernatural strength

Royal Melbourne Institute of Technology (RMIT) researchers have 3D printed titanium 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.

RMIT University researchers created the new metamaterial, a term used to describe an artificial material with unique properties not observed in nature, from common titanium alloy. 

It’s the material’s unique lattice structure design, recently revealed in the journal Advanced Materials, that makes it anything but common.

Tests show it’s 50 per cent stronger than the next strongest alloy of similar density used in aerospace applications. 

Study lead author and RMIT PhD candidate Jordan Noronha said, “Compared with the strongest available cast magnesium alloy currently used in commercial applications requiring high strength and light weight, our titanium metamaterial with a comparable density was shown to be much stronger or less susceptible to permanent shape change under compressive loading, not to mention more feasible to manufacture.” 

The team 3D printed this design at RMIT’s Advanced Manufacturing Precinct using a process called laser powder bed fusion, where layers of metal powder are melted into place using a high-powered laser beam.

“Traditional manufacturing processes are not practical for the fabrication of these intricate metal metamaterials, and not everyone has a laser powder bed fusion machine in their warehouse,” said Noronha.

Testing showed the printed design, a titanium lattice cube, was 50 per cent stronger than cast magnesium alloy WE54, the strongest alloy of similar density used in aerospace applications.

The new structure had effectively halved the amount of stress concentrated on the lattice’s infamous weak points.

The double lattice design also means any cracks are deflected along the structure, further enhancing the toughness.  

The team plans to further refine the material for maximum efficiency and explore applications in higher-temperature environments.

While currently resistant to temperatures as high as 350 °C, they believe it could be made to withstand temperatures up to 600 °C using more heat-resistant titanium alloys, for applications in aerospace or firefighting drones.  

Technical director of RMIT’s Advanced Manufacturing Precinct, distinguished professor Milan Brandt said, “Our approach is to identify challenges and create opportunities through collaborative design, knowledge exchange, work-based learning, critical problem-solving and translation of research.” 

As the technology to make this new material is not yet widely available, its adoption by industry might take some time.

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