Australian researchers at RMIT University have developed a 3D-printed titanium lattice structure that floats in water while maintaining strength and durability, even after damage occurs.

Key Innovation

The material combines hollow titanium struts filled with polyurethane foam. As Dr. Jordan Noronha explained, “By filling only the hollow titanium struts with polyurethane foam, we created a structure that allows water to flow through it while remaining buoyant even after significant cracking and damage.”

The Skeletal Density Breakthrough

Researchers introduced a new measurement called skeletal density, which calculates buoyancy based only on water-excluding materials rather than total volume. This approach provides engineers with a practical design principle for predicting flotation.

Performance Metrics

Testing demonstrated the titanium structure was 70% stronger than stainless steel or high-density polyethylene at equivalent densities. In seawater corrosion tests, the material lost only 0.15% mass over two weeks while strength declined less than 1%.

Critically, the structure maintained buoyancy despite significant damage, sinking only after severe crushing.

---

Journal: Advanced Materials
DOI: 10.1002/adma.74641
Article Title: Breaking the surface: buoyant metal–polymer open–cell hybrid lattice metamaterials
Publication Date: 28-Aug-2026
Institution: RMIT University
Funding: Australian Research Council

Source: EurekAlert