In Situ Alloying of H13 Tool Steel With TiC via PBF‐LB/M

In situ alloying via laser‐based powder bed fusion of metals (PBF‐LB/M) has gained attention as an alternative to prealloyed powders. In this study, H13 tool steel is in situ alloyed with titanium carbides (TiC) in amounts up to 30 wt.%. This approach offers the advantage that the carbides melt only partially during processing, preventing excessive carbon enrichment of the steel matrix. Using suitable process parameters, samples with up to 15 wt.% TiC were successfully fabricated with relative density above 99.6 vol.%. The resulting microstructure consists of coarse, undissolved and fine, reprecipitated carbides, leading to grain refinement and an isotropic microstructure. By varying the scanning speed, the energy input and thus the degree of carbide dissolution can be controlled. As‐built hardness values for powder mixtures with 10 wt.% TiC reach 590 HV30, which is higher than the maximum hardness achieved through subsequent hardening. The secondary hardness peak is reached with direct tempering for 4 h at 500°C with 659 HV30.