Age-Hardening Behavior in High-Nitrogen Stable Austenitic Stainless Steel

Abstract

Age hardening in stable austenitic stainless steel wires with a chemical composition of Fe18%Cr12%Ni and different N contents was investigated to clarify the role of N. Age hardening could be enhanced by increasing the drawing ratio and N content. The highest age-hardening effect was observed at 800 K in the N-bearing specimens. In addition, severe drawing induced low-temperature age hardening at 450600 K. Differential scanning calorimetry (DSC) analysis revealed that age hardening at 800 K may be attributed to particle dispersion strengthening by Cr 2 N. Meanwhile, the exothermic peaks observed at 450600 K were controlled by the pipe diffusion of N. However, nitride precipitates and clusters could not be detected by 3D atom probe analysis, which implies the formation of atomic-scale N products, such as I-S pairs, at the dislocations.