Development Of A Carbide-rich Cold Work Tool Steel Through In-situ Alloying In PBF-LB|M

Laser beam powder bed fusion of metals (PBF-LB|M) provides exceptional geometric freedom, but the variety of processable materials remains limited. In particular, the precise control of specific microstructures, like coarse carbides for better resistance against abrasive wear, continues to present challenges in research. In this study, hot work tool steel powder was mixed with high-speed steel (HSS) powder and titanium carbides (TiC) to develop an in-situ alloyed carbide-rich cold work tool steel.Thermodynamic calculations were performed to design an alloy system leading to a promising microstructure. During processing, TiC partially dissolved, resulting in coarse undissolved carbides and reprecipitated primary carbides. Carbide-forming elements like molybdenum (Mo), vanadium (V) and tungsten (W) are added as HSS powder to enhance the alloy´s potential for secondary hardening. The influence of PBF-LB|M process parameters on resulting carbides were analysed. In-depth microstructure analyses were conducted using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD).