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

Fangjie Mo,Hong Wang,Guangai Sun,Zhao Liu,Zukun Yang,Jian Gong,Ying Chen,Hongjia Li,Shuming Peng,Jian Li,Yalin Huang,Changsheng Zhang,Beibei Pang,Yi Tian,Zhaolong Yang,Bo Chen

doi:10.3390/qubs2030015

Abstract

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.

Highlights

Residual stress, which originates from the inconsistent distortion between different regions, can be defined as self-balanced internal stress remaining inside materials and components after external stress or non-uniform temperature fields are eliminated
The structure and internal stress in components such as turbine discs, blades, and welding parts are able to be studied by neutron diffraction, offering valuable results of multiple reflections of poly and single crystal materials
Residual Stress Neutron Diffractometer is a pragmatic tool for accessing the structure and distribution of the stress inside materials and components for reliability assessments

Summary

Introduction

Residual stress, which originates from the inconsistent distortion between different regions, can be defined as self-balanced internal stress remaining inside materials and components after external stress or non-uniform temperature fields are eliminated. The structure and internal stress in components such as turbine discs, blades, and welding parts are able to be studied by neutron diffraction, offering valuable results of multiple reflections of poly and single crystal materials. Compared with the Residual Stress Diffractometer (RSD) at the CARR in Beijing (Table 1), the technical characteristics of the RSND at the CMRR show great superiority, including a more flexible neutron wavelength, wider diffraction angle range, and greater loading capacity. The evolution of structure in single crystal materials and components can be successfully tracked by in situ neutron diffraction. WWhheenn eeqquuiippppeedd wwiitthh ootthheerr iinnssttrruummeennttss,, ssuucchh aass aa llooaaddiinngg ffrraammee,, KKaappppaa ggoonniioommeetteerr,, aanndd ccoouupplliinngg ssyysstteemm,, tthhee RRSSNNDD ccaann aallssoo bbee uusseedd ttoo eeffffeeccttiivveellyy mmeeaassuurree tthhee tteexxttuurree aanndd iinn ssiittuu eevvoolluuttiioonn ooff tthhee llaattttiiccee

Application Research Examples Using Residual Stress Neutron Diffractometer

Quenching-Induced Residual Stress in GH4169 Superalloy

Summary and Future Prospects