Simultaneous characterisation of precipitates and matrix in a steel using small-Angle neutron scattering and bragg-edge transmission analysis

Abstract

A new technique for the quantitative characterisation of the microstructure in steels has been developed. Using a small-Angle neutron scattering (SANS) instrument at a pulsed neutron source, both a SANS profile and a Bragg-edge transmission spectrum could be simultaneously measured. The SANS analysis provides structural information about the precipitates in steels, while the Bragg-edge transmission analysis reveals the crystal structure of the steel matrix. As a demonstration, Fe-C-Cu-V alloys were measured and analysed. The SANS profiles showed that nanosized precipitates were grown when the alloys were aged at 823 K. The Bragg-edge of the corresponding transmission spectra clearly revealed that the ferritic matrix was kept with the aging time. The experimental results confirmed that this new technique provides a new possibility of efficient characterisation of the steel microstructures.