ENCOMPASS - Design of Enhanced Metal Matrix Composites for Additive Manufacturing of Space Structures - has concluded. The European Space Agency project focused on the development of new composite materials and processes for the additive manufacturing of structural components for the space sector.
The project brought together six partners: Politecnico di Milano, Leonardo, Thales Alenia Space Italia, Łukasiewicz Research Network - Institute of Aviation, BEAMIT and Politecnico di Torino, under ESA technical supervision. From the Department of Mechanical Engineering at Politecnico di Milano, Prof. Riccardo Casati, project coordinator, Prof. Professor Luca and Prof. Stefano Beretta took part in the initiative, together with Giorgia Lupi and Luca Mariotti, who carried out their doctoral research within the project.
The objective was to design and validate an aluminium-matrix material able to overcome the limitations of alloys commonly used in metal 3D printing, providing higher stiffness and mechanical strength without compromising manufacturability.
The central outcome of ENCOMPASS is the development of an Al2618-TiB₂ composite: an aluminium alloy reinforced with titanium diboride ceramic particles. The feedstock was produced by combining two approaches: the in-situ formation of TiB₂ during powder atomisation and the controlled ex-situ addition of particles through high-energy mechanical mixing. This solution enabled a reinforcement content of approximately 7 wt.%.
The experimental work resulted in a complete manufacturing route, including powder production and qualification, Laser Powder Bed Fusion (LPBF) parameter optimisation, heat treatments, microstructural and mechanical characterisation, and the design and testing of demonstrators. TiB₂ promoted microstructural refinement, eliminated solidification cracking and improved the properties of the printed material. The composite achieved a 15% increase in elastic modulus, an ultimate tensile strength of 459 MPa and a yield strength of 433 MPa, while maintaining fracture toughness and fatigue resistance competitive with other aluminium alloys produced by additive manufacturing.
Two demonstrators translated these results into representative hardware. For Leonardo, a bipod for the isostatic mounting of optical equipment was developed, integrating three in situ techniques for fatigue-damage monitoring. For Thales Alenia Space Italia, a bottom panel for a satellite platform was developed, manufactured in subcomponents and assembled by structural bonding, demonstrating the possibility of extending the approach to larger structures.
The project also highlighted key priorities for future work: strict control of humidity and powder handling, optimisation of contour parameters to reduce surface defects, and the development of heat treatments specifically tailored to composite materials. ENCOMPASS therefore lays the groundwork for lighter, stiffer and higher-performance space components for future ESA missions.