Recent Progress of Residual Stress Distribution and Structural Evolution in Materials and Components by Neutron Diffraction Measurement at RSND

Neutron diffraction is an effective and nondestructive method to investigate inner structure and stress distribution inside bulk materials and components. Compared with X-ray diffraction, neutron diffraction allows a relatively high penetration depth and covers a larger gauge volume, enabling it to measure the lattice structure and three-dimensional (3D) distribution of residual stress deep inside thick sample materials. This paper presents the recent development of a Residual Stress Neutron Diffractometer (RSND) at the Key Laboratory for Neutron Physics of the Chinese Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang, China. By integrating multiple instruments such as a loading frame, Kappa goniometer, and coupling system, the RSND was constructed as a suitable platform for various neutron diffraction experiments, including residual stress measurement, in situ observation, and texture analysis. Neutron diffraction measurement can be used to study various materials such as steels, aluminum alloys, and titanium alloys, as well as various components such as turbine discs and welding parts. An evaluation method for both polycrystalline and monocrystalline materials was developed, and this method was found to have the capability of solving an agelong technical challenge in characterizing monocrystalline materials. Furthermore, by introducing a texture and thermomechanical coupling system, it is now possible to make effective in situ observations of the structural evolution in single crystal materials under high-temperature tensile conditions.