PVD duplex treatment of AISI M2 high-speed steel additively manufactured by metal binder jetting

Among additive manufacturing techniques, metal binder jetting (MBJ) offers high build rates and cost-efficient manufacturing, making it attractive for large-scale production of tooling components. However, MBJ produced AISI M2 high-speed steel exhibits a distinct microstructure compared with conventionally manufactured material, and its influence on physical vapor deposion (PVD) duplex treatments has not yet been systematically investigated. Therefore, the effect of the manufacturing route on plasma nitriding and subsequent TiAlN deposition is evaluated by comparing MBJ produced and conventionally manufactured steel variants. Both steels are plasma nitrided at 420 °C for 4 h and subsequently coated with TiAlN using cathodic arc evaporation. Plasma nitriding results in nitrogen supersaturation of the martensitic matrix, producing a diffusion depth of 20 µm and pronounced surface hardening in both steels. TiAlN thin films exhibit comparable hardness (32–34 GPa) and dense morphologies independent of the substrate condition. While plasma nitriding slightly increases the coefficient of friction up to 6%, it significantly reduces the wear rate up to 29% of the TiAlN-coated MBJ produced steel variant. Overall, MBJ produced AISI M2 showed a plasma nitriding response comparable to conventional steel, demonstrating that established PVD duplex treatments can be successfully transferred to additively manufactured tool steels.