Powder Metallurgy and Additive Manufacturing of High‐Nitrogen Alloyed FeCr(Si)N Stainless Steel

Nitrogen, as an alloying element in stainless steels, is valued for its ability to enhance strength, corrosion resistance, and its strong austenite‐stabilizing effect. Compared to other elements like nickel and manganese, nitrogen is more accessible, biocompatible, and cost‐effective, making it ideal for sustainable and economical austenitic stainless steel production. This study explores a powder metallurgical approach to produce an austenitic stainless steel based on the FeCr(Si)N alloy system. A powder mixture of Fe20Cr and Si 3 N 4 is hot isostatically pressed (HIP), dissolving Si 3 N 4 and enriching the matrix with nitrogen. While a primarily austenitic microstructure is formed, small martensitic regions appear due to localized silicon segregation (lower austenite stability). The same powder mixture was used in the laser powder bed fusion (PBF‐LB/M) process to manufacture shell–core samples. In this method, a partially powdered core is encased by a dense shell, with subsequent HIP ensuring full compaction and dissolution of the remaining Si 3 N 4 particles in the powdered regions. However, an Si 3 N 4 decomposition reaction during PBF‐LB/M results in nitrogen loss, leading to a martensitic–ferritic microstructure instead of an austenitic one. Optimization strategies to achieve an austenitic FeCr(Si)N microstructure also in the PBF‐LB/M process, which is particularly relevant for medical technology, are presented.