Influence of nitrogen alloying on properties of Fe-18Cr-12Mn-XN austenitic stainless steels

In the present work, influence of nitrogen alloying on mechanical and corrosion properties of metastable Fe-18Cr-12Mn-XN alloys was investigated. It was observed that stacking faults and epsilon-martensite needles decreases with N, conversely, short range ordering and deformation twinning increases. Further, it was found that yield strength and hardness of the alloys linearly increases with N. In contrast, elongation and tensile strength of the alloys changed nonlinearly with increasing N. Influence of N on mechanical properties was mainly related to its effect on solid solution strength and deformation-induced alpha-martensitic transformation. SEM fractography of the samples showed a ductile fracture for N-bearing samples. It was observed that N-alloying enhances the corrosion resistance of the alloys. In addition, it was revealed that corrosion resistance of the studied alloys is well comparable with Ni-containing austenitic stainless steels and superior to other ultrahigh strength steels. (C) 2013 Elsevier B.V. All rights reserved.