High resolution texture measurement by using neutron diffraction

中性子回折による高分解能集合組織測定技術

徐 平光   ; Harjo, S.   ; 小貫 祐介*; 佐藤 成男*; Lutterotti, L.*; Vogel, S. C.*; Liss, K.-D.*; 富田 俊郎*

Xu, P. G.; Harjo, S.; Onuki, Yusuke*; Sato, Shigeo*; Lutterotti, L.*; Vogel, S. C.*; Liss, K.-D.*; Tomida, Toshiro*

For polycrystalline materials, textures as their crystallographic orientation feature have been paid broad attention because of their important effects on mechanical and physical characteristics. Besides metals and ceramics, the widespread applications of textures involving sheet forming simulation, additive manufacturing, minerals, and rocks have also demonstrated this status. Different with the electron backscattering diffraction (EBSD) and the X-ray diffraction (XRD) for surface texture analysis, the neutron diffraction thanks to the excellent penetrability and the coarse beam spot of thermal neutrons can collect high statistical diffraction pattens, valuable for deeply investigating the microstructure change and the characteristic response of polycrystalline materials. Through the Rietveld texture analysis process combined with other profile-analysis-related material parameters (e.g. stress tensor, phase fraction, dislocation density and/or coherent size), the large-scale neutron diffractometers TAKUMI and iMATERIA with good instrumental resolution (d/d) and high beam flux have higher measurement efficiency, promoting that the precise evaluation of microstructures and related materials parameters of advanced materials. Recently, weak diffraction patterns step-by-step collected in very short time from the RESA angle dispersive neutron diffractometer at JRR-3 have been utilized to realize the precise texture evaluation of various polycrystalline materials. Our international round robin activity for texture analysis confirms that, Rietveld texture analysis using MAUD software may be recommended as a standard bulk texture analysis method, regardless of the neutron source types of steady reactor source or time-pulsed source.