Characterisation of γ' precipitates in single crystal nickel-base superalloy SC16 by small angle neutron scattering

Characterisation of the microstructure of the single crystalline nickel-base superalloy SC16 by small angle neutron scattering (SANS) is presented. Specimens heat treated to produce γ' precipitates of different sizes were investigated. The two-dimensional SANS scattering patterns exhibited isotropic or anisotropic character depending on the heat treatment. Data analysis was carried out using a modeling method specially developed for γ' precipitates in superalloys with high γ' volume fractions. A diffraction peak indicating an influence of interparticle interference was observed in one case allowing to calculate the average distance between precipitates. An estimate of the γ' volume fraction after different heat treatments was made. (orig.)