Influence of cold work on the diffusion of ion-implanted nitrogen in D9 steel using nuclear reaction analysis

D9 steels and their modified versions are envisaged for use as fuel cladding and wrapper materials in the Indian fast breeder reactor (FBR) programme. The role played by interstitially dissolved nitrogen in steel matrices for the stabilization of austenitic phase, increase of strength and corrosion resistance is well known. Various factors: the role of grain boundaries and the their orientation, stress mediation, grain fragmentation and production of short circuit paths as a result of compressive stress are known to affect the diffusion of nitrogen. Basically, cold working produces plethora of defects throughout the sample as compared to its solution annealed state. Our earlier studies on 1 x10¹⁵ and 5x10¹⁵ N¹⁵ implanted Solution Annealed D9 (SAD9) showed significant vacancy-nitrogen complexes for higher fluence. Hence, thermal diffusion behaviour of nitrogen was studied in 5 x10¹⁵ -N¹⁵ implanted samples in solution annealed state. In the present study, to understand the influence of cold work, similar thermal diffusion behaviour of nitrogen has been studied in Cold Worked D9 steel (CWD9) using nuclear reaction analysis