Particle-reinforced Tool Steels Through Powder Additivation in Laser-based Powder Bed Fusion

Laser-based powder bed fusion (PBF-LB) is still rarely applied due to the limited range of available alloys. Powders of carbide containing tool steels have a low weldability and a high cracking tendency during processing. Additions of high-melting carbides to an easily processable steel in the powder feedstock enables a higher carbide content in the alloys without affecting the processability. In this study, AISI H13 base steel was modified by additions of 5 wt.-% edged TiC. TiC remain as partially unmolten particles within the steel matrix and enhance macro hardness and wear resistance of the alloy while enabling a stable processing of crack-free alloys. Supplementary in-depth microstructure analysis by EBSD and texture analysis were performed and a shift towards isotropic microstructures was observed. The TiC act as nucleation sites for equiaxed grain growth during solidification, which eliminates the typical epitaxial grains in building direction and potentially reduces the anisotropy of mechanical properties.