The suitability of SANS for microstructural investigation of materials for high-temperature applications is highlighted. The presented examples of SANS application were oriented namely to the characterization of microstructure of Ni-base superalloys. The bulk parameters of single-crystal alloy SCA433 were determined from the measured 2D data at two sample. orientations. The in-situ SANS study of polycrystalline alloy Re13 led to the determination of the suitable solution treatment procedure.