How RMIT Researchers Made 3D Printed Titanium Float on Water

Researchers at RMIT University have created the first buoyant metal-polymer open-cell hybrid lattice metamaterial that floats in water, addressing a fundamental incompatibility between porous metal architectures and buoyancy.

Published in Advanced Materials, the study introduces a hybrid architecture that combines 3D printed titanium lattices with injected polyurethane foam to achieve skeletal densities below 1.0 g/cm³. The breakthrough matters because it decouples buoyancy from the loss of external open-cell permeability.

Conducted at RMIT’s Centre for Additive Manufacturing (RCAM) with collaborators at the Conservatoire National des Arts et Métiers (CNAM) in Paris, the research rests on a reframing of how density should be calculated for porous structures immersed in liquid. Convention