Carbide‑Reinforced High Speed Steel M2 Layers for Forming Tool Applications: A DED‑LB Study on Particle Size Effects

Direct Energy Deposition (DED LB) with powder feedstock has emerged as an effective method for restoring forming tools and applying functional surface layers to both new and refurbished components. With modern systems capable of dosing multiple powders simultaneously, it is possible to create compositionally graded and heterogeneous material system. This study concentrates on protective layers intended for forming tools, produced from high speed steel M2 enriched with 5–20% tungsten carbide (WC) or titanium carbide (TiC). Particular attention was given to how the size of the reinforcing particles—ranging from nanoscale to micrometer scale—affects the resulting microstructure and mechanical performance of the deposited layers. A comprehensive experimental program, including SEM, mechanical testing, and wear evaluation, revealed that the combined addition of WC and TiC significantly improves wear resistance and strength. The use of nanosized carbides promotes finer dispersion and microstructural refinement while preserving structural stability under the applied processing conditions.