Additive manufacturing of Fe-TiB2 metal matrix composites: an investigation of microstructure and properties

Fe-TiB₂ composites are of significant interest due to their unique combination of properties, such as enhanced specific stiffness, and a favorable balance of stiffness and ductility, making them ideal for structural applications. However, despite their potential, these composites are not yet commercially available, largely due to the challenges associated with traditional production methods such as powder metallurgy and continuous casting, which are often energy-intensive and difficult to scale for large components. Metal additive manufacturing (MAM), particularly the Directed Energy Deposition-Laser Powder (DED-LBp) process, offers a promising alternative for producing metal matrix composites, allowing for improved material efficiency, reduced waste, and greater design flexibility. This study investigated the development of pure Fe matrix composites reinforced with TiB₂ particles using the DED-LBp process. The microstructure, hardness, elemental composition, and corrosion resistance of the produced Fe-TiB₂ composites, which exhibited a TiB₂ volume fraction of 29%, were analyzed and compared to ArcelorMittal’s Fe-13v%TiB₂ composite sheet manufactured by continuous casting. The study showed that DED-LBp is a successful method for fabricating Fe-TiB₂ composites with a microstructure similar to that of conventionally produced materials. Corrosion tests in a chloride environment (NaCl 3%) revealed that the corrosion behavior of the DED-LBp deposits was comparable to that of unalloyed steel, with no significant improvement conferred by the TiB₂ particles, and similar to the ArcelorMittal sheet. However, further research is needed to optimize the chemical composition to control the volume fraction of primary TiB₂ particles and to comprehensively evaluate mechanical properties for structural applications.