Effects of nitrogen concentration and plastic deformation on small angle neutron scattering for austenitic stainless steels

Abstract

Synopsis : The small angle neutron scattering (SANS) profile has been found to be influenced by nitrogen addition and plastic deformation for austenitic stainless steels. In solution-treated specimens, the slope of plots for SANS intensity versus the magnitude of scattering vector, q, becomes larger than -4 in the Porod region, suggesting the influence of short range N ordering. The change in scattering intensity profile with tensile deformation was in situ measured and it is found that SANS intensity becomes larger with increasing of plastic strain except a q region around 0.6 nm-1 for N bearing steel, where the intensity decreases in the beginning and then increases with increasing of plastic strain. This temporary decrease in SANS intensity is confirmed for cold rolled specimens. Severe deformation given by swaging to a N free steel brings larger increase in SANS intensity than a N bearing steel. The influence of plastic deformation on SANS intensity is larger in austenitic steels than in ferritic steels.