A Perspective on Powder Metallurgy and Additive Manufacturing of High‐Nitrogen Alloyed Stainless Steels

Incorporating nitrogen as an alloying element in stainless steels can significantly enhance their mechanical and chemical properties. However, the limited solubility of nitrogen, particularly in the liquid phase, presents challenges. This perspective article explores an innovative powder metallurgical approach to producing high‐nitrogen steels (HNS) by utilizing a mixture of stainless steel and Si₃N₄. This mixture undergoes hot isostatic pressing (HIP) followed by direct quenching, facilitating diffusion alloying, and solution annealing in a single step. The article also examines adapting this method to powder bed fusion of metals using a laser beam (PBF‐LB/M) to overcome nitrogen solubility limits, which currently constrain the achievable nitrogen content in PBF‐LB/M‐manufactured stainless steels. The approach aims to retain Si₃N₄ particles within the matrix during PBF‐LB/M to enrich the steel with nitrogen during subsequent HIP. However, laser interaction with Si₃N₄ can lead to nitrogen loss, prompting an alternative strategy: a shell–core structure based on a gas‐tight shell enclosing loose Si₃N₄ particles. These particles dissolve during HIP, enriching the matrix with nitrogen and enabling the production of HNS. This article highlights the potential for extending this approach to other stainless steel groups, broadening the possibilities for HNS production through both conventional HIP and PBF‐LB/M manufacturing routes.