Numerical study of microstructural changes in damage alloy (steel) by SANS

The quantitative determination of damage is important as a starting point for residual lifetime predictions. Damage can be due to creep, fatigue, oxidation and corrosion. Precipitates, dispersions and cavities are inhomogeneities contributing to material degradation and damage. SANS (Small Angle Neutron Scattering) is capable of detecting these microstructural parameters. The scattering signal is the total of scattering processes of all these features. The size range suitable for this technique is between 1 and 300 nm. The paper presents basic numerical approach of using SANS for detecting material damage and correlating to the residual life time. The scattered intensity originates in principle from atom core scattering density difference. Structural parameters such as volume fraction, scattering length and size are considered in the establishing scattered neutron intensity profile. (author)