Influence of an Increasing Alloying Content on the Microstructure of a High‐Speed Steel in the Laser‐Powder Bed Fusion Process

Tool steels being processed by laser powder bed fusion (LPBF) receive increasing attention in research. High hardness and low toughness lead to a challenging crack susceptibility of these alloys. Latest advancements in process technology have shown promising results toward crack‐free build‐up of additive manufactured tools. Detailed microstructure analysis is carried out to understand the mechanisms of solidification as an influencing factor for cracking. These findings can provide insights toward an alloy optimization regarding a higher intrinsic crack resistance while maintaining the typical mechanical properties of tool steels. PMHS 6–5–3–8 high‐speed steel shows directional dendritic solidification with carbides mainly precipitating in enriched interdendritic areas. Increasing the alloying content by additions of PMHS 7–7–7–11 leads to a shift toward a less‐pronounced texture. The positive effect of texture reduction is superimposed by a highly increased crack formation due to carbide networks.