Engineering materials characterization techniques using neutron diffraction

Xu, P. G.   ; Morooka, Satoshi  ; Shibayama, Yuki; Sasaki, Miki; Yamamoto, Kazuyoshi ; Shobu, Takahisa  

Different with the electron backscattering diffraction (EBSD) and the X-ray diffraction for surface layer analysis, the neutron diffraction can collect bulk diffraction information thanks to the coarse beam spot and several ten mm penetrability of the thermal neutrons in most engineering materials, valuable for deeply investigating microscopic microstructure changes and macroscopic mechanical/physical responses of polycrystalline materials. Thanks to close cooperation among international/domestic universities and institutes, Japan has entered a new era of stress and texture evaluation technique using various neutron instruments involving in a steady-state reactor neutron source at Japan Research Reactor No.3 (JRR-3), a large spallation neutron source at J-PARC, and a compact neutron source at RANS. Recently, JRR-3 has restarted to support the neutron diffraction experiments of various engineering materials and realized several interesting research examples. Texture is the crystallographic preferred orientation state of grains in polycrystalline materials, and its optimization may improve the mechanical/physical anisotropic behavior of engineering materials and product parts, leading to an evident economic benefit for such as automobile steel sheets, oriented silicon steel sheets. Nondestructive stress measurement is another important industrial application of RESA neutron instrument, unique to evaluate the strain and stress state inside materials deep to several tens of mm. It contributes significantly to the design and manufacture of mechanical structures aimed at high performance, high reliability and long life, and improves the reliability and structure integrity of a wide range of machinery and structures. We welcome more academic and industrial users to make good use of these large-scale neutron science facilities to nurture more globally competitive talents, achieve world-leading research results and economic benefits.