Distribution of interstitial impurities and their diffusion parameters in high-nitrogen steels studied by means of internal friction

The interstitial impurities distribution and their diffusion in three austenitic steels with high nitrogen content were studied via internal friction (IF) method. Analyses of the relaxation spectra of nitrogen Snoek-peaks in N-containing stainless steels revealed that N atoms preferably occupy octahedral interstitial sites with maximum number of Cr atoms in the vertices. Only partially filled types of interstitial sites contributed to the relaxation and thus, to diffusion. The types of partially filled sites changed with changing N content and the effective diffusion coefficients appeared to be dependent on the average N content in solid solution.