The neutron spectroscopy proof of the strong Cr-N interactions in nitrogen stainless steels

The existence of the strong Cr-N interaction in Fe-(Cr, Mn, Ni)-N was proved by the neutron spectroscopy. The force constant of the Cr-N interaction is 30 % higher and the value of its potential depth is twice greater than that of metal-nitrogen or carbon pairs. Due to this strong interaction nitrogen is trapped by Cr-clusters inside the austenite lattice. This has great consequences: a decrease of the dislocation flowing and diffusion both of N and Cr atoms, an increase of the austenite stability. Really, this interaction explains advantages of the nitrogen steels before carbon ones. The spectroscopy data do not show the changing of the random distribution of the metal atoms in the Fe-Cr austenitic matrix just after austenization treatment. (author)