Direct laser powder-bed fusion additive manufacturing of complex-shaped TiB2-B4C composite with ultra-fine eutectic microstructure and outstanding mechanical performances

TiB 2 -B 4 C had various outstanding properties and great potentials in versatile high-end application fields, and thus the preparation of its monolithic counterpart with arbitrary topology was eagerly demanded. However, due to their intrinsically strong covalent-bonding and poor laser absorption performances, it was still highly-challenging to prepare TiB 2 -based composite by additive manufacturing method. Herein, by using direct laser powder-bed fusion additive manufacturing (selective laser sintering) and the unique strategy of in-situ synthesizing/sintering, complex-shaped TiB 2 -B 4 C composite was successfully additively manufactured for the first time. More importantly, benefiting from their ultrafine eutectic microstructures and high relative densities, the resultant TiB 2 -B 4 C composite exhibited outstanding Vickers hardness and fracture toughness of respectively up to 35.6 GPa and 8.6 MPa·m 1/2 , which were remarkably higher even than that of the highly-dense counterparts prepared by subtractive methodologies. This work is anticipated to offer a reliable route for near-net-forming high-temperature ceramic-matrix composite with arbitrarily-complex topology and superior mechanical-performances.