On the mechanism of nitrogen effect on plasticity of chromium-manganese steels

Using temperature and amplitude dependences of internal friction a study was made into the influence of nitrogen on mechanical properties of the steel containing 0.03% C, 17.05% Cr, 8.92% Mn. Nitrogen contents in steel constituted 0.06, 0.2 and 0.40%. The mechanism of nitrogen effect is shown to relate to the behaviour of dislocations in crystal lattice in dependence on nitrogen distribution between solid solution and second phase. It is concluded that nitrogen promotes an increase of steel strength and a decrease of plasticity due to its effect on dislocation mobility. As an interstitial impurity nitrogen enhances the resistance of crystal lattices to dislocation motion and decelerates the process of stress relaxation.