The most interesting engineering breakthroughs do not always come from inventing a new material. Sometimes, they come from discovering how to make a familiar one behave in an entirely unexpected way.
This article explores three engineering lessons from a floating titanium that challenges conventional thinking about material behavior, structural design, and how familiar materials can be engineered to perform in unexpected ways.
Dense materials can be engineered to behave differently by changing their structure. Titanium, for example, is valued for its strength and low weight relative to steel. According to the U.S. Geological Survey (USGS), titanium is about 45% lighter than steel. However, with a density of approximately 4.5 g/cm³, it is still around 4.5 times denser than water, meaning a solid piece of titanium sinks.
Researchers at RMIT University in Australia tackled this challenge by using 3D printing to create a titanium lattice, an open framework of interconnected struts, which they filled with lightweight polyurethane foam. Together, the titanium lattice and the foam lowered the structure’s overall density, making it enough for it to float while titanium itself retained its structural strength.
This research illustrates how combining structural design with complementary materials can expand the potential uses of an existing metal such as titanium. A material’s density may appear to limit its use in buoyant structures, but its suitability and performance can change when its weight, structural arrangement, and interaction with other materials are considered together. This can reveal design possibilities that may not be apparent when evaluating a material on its own.
Conventional manufacturing methods can make complex designs difficult or expensive to produce, which limits the shapes and structures engineering professionals can create. As a result, the choice of manufacturing technology can influence how a component is designed and what forms it can take. In the RMIT University research, 3D printing allowed researchers to create a titanium lattice with an open network of thin, interconnected struts and open spaces between them. Creating this intricate geometry allowed the researchers to explore alternatives to solid components and to control the structure’s internal arrangement rather than relying on a solid piece of the metal alone.
This shows how using a manufacturing technology like 3D printing can expand the range of designs.
A 2024 study on “Additive Manufacturing-Enabled Advanced Desing and Process Strategies for Multi-Functional Lattice Structures” provides further supports this idea by examining the design possibilities offered by additive manufacturing. Other methods, such as investment casting and advanced composite manufacturing, also allow engineering professionals to tailor material properties to suit specific applications.
The key is to evaluate the material, consider suitable additives, and select a manufacturing approach that meets the component’s intended function rather than limiting the design to what is easiest to produce.
Some engineering applications require a combination of material properties that a single material may not provide. Combining materials with complementary strengths can help engineering professionals meet multiple performance requirements.
In the RMIT University research, titanium provides structural strength while the lightweight polyurethane foam helps the structure float. This approach could inform the development of floating structures that need to balance buoyancy with structural performance, although further testing would be needed to establish their suitability for specific marine applications.
The same principle applies beyond buoyancy. A 2022 study on “Hybrid Materials Based on Polymers-Filled AM Steel Lattices with Energy Absorption Capabilities” found that combining a metal lattice with a polymer could increase energy absorption by up to 75% beyond the combined energy absorbed by the metal lattice and polymer separately. Similarly, a 2024 study on “Compressive Behavior of Triaxially Braided Metal-CFRP Hybrid Lattice Structures” reported a 62% improvement in specific energy absorption through hybridization. These findings suggest that the benefit of combining materials lies not simply in bringing different properties together, but in how those materials work together to improve a structure’s response to specific demands.
The floating titanium discovery shows how engineering decisions can expand what a material can achieve. It highlights the importance of questioning conventional design assumptions and exploring alternatives when a material’s usual properties appear to be limiting.
At the Engineering Institute of Technology (EIT), courses in Civil and Mechanical engineering provides relevant foundations in engineering design and structural principles. By studying how materials and structures behave under different conditions, students can build the knowledge needed to assess design choices and approach engineering challenges from new perspectives.
References
Titanium-Light Strong, and White
Engineers create a world-first in floating titanium
Hybrid Materials Based on Polymers-Filled AM Steel Lattices with Energy Absorption Capabilities
Compressive Behavior of Triaxially Braided Metal-CFRP Hybrid Lattice Structures
This article was published November 5th, 2026 and the content is current as at the date of publication.
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