Laser powder bed fusion of TaC-reinforced FV520B maraging steel with simultaneous enhancement of mechanical properties and corrosion resistance

Additive manufacturing, colloquially referred to as 3D printing, enables the direct printing of complex maraging steel components. However, it remains challenging to improve the strength of 3D-printed maraging steels without seriously impairing their ductility. Here we report a dispersion-strengthening strategy for the fabrication of maraging steels with enhanced strength and acceptable ductility via the addition of TaC particles. The micro-sized TaC particles convert to finely dispersed high-density nanoparticles and contribute to the strengthening of the as-built specimen. The dissolved TaC solute suppresses martensitic transformation upon cooling and results in the formation of the austenite/martensite duplex microstructure. In addition, the elemental segregation and high-density dislocations network contribute to the formation of the cellular structure. Consequently, the microstructural changes due to the TaC addition result in an exceptional synergy of strength-ductility and significantly enhanced corrosion resistance. This work provides a promising way to fabricate dispersion-strengthened maraging steels with high overall performance.