Multiple wavelengths texture measurement using angle dispersive neutron diffraction at WOMBAT

徐 平光; Liss, K.-D.*

Quantum Beam Science (Internet), 5(2), p.11_1 - 11_14, 2021/06

AA2020-0801.pdf:11.28MB

https://doi.org/10.3390/qubs5020011

In contrast to conventional angle dispersive neutron diffractometers with a single-tube detector or a small-size linear position-sensitive detector, the WOMBAT diffractometer at Australian Nuclear Science and Technology Organisation (ANSTO) is equipped with a large-area curved position-sensitive detector, spanning 120 for the scattering angle 2 and 15 for the azimuth , respectively. Here, WOMBAT was employed to establish a texture measurement environment for complex textured samples, through measuring neutron diffractograms at two selected wavelengths on a typical reference sample of martensite-austenite multilayered steel sheet. All neutron patterns were simultaneously Rietveld analyzed using the software, Materials Analysis Using Diffraction (MAUD). The shorter wavelength enabled to collect the martensite diffraction peaks 110, 200, 211, 220, 310, 222 as well as the austenite diffraction peaks 111, 200, 220, 311, 222, 331 diffraction peaks simultaneously by pre-setting the detector range to 2 = 30150. The longer wavelength enabled to separate the overlapping strong martensite peak 110 and austenite peak 111 more reliably. Moreover, the detector panel division along the vertical direction covers a good stereographic coverage in the azimuthal angle. Such combination of multiple wavelength neutron diffraction combined with simultaneous Rietveld texture analysis was confirmed much valuable to realize high precision measurements for complex textured samples at an orientation distribution function (ODF) graticule of 5, and in a much shorter beam time than the conventional angle dispersive method.

Molecular motion and structure of unsintered polytetrafluoroethylene, 3; Texture from the measurement of 100 Debye-Scherrer line profiles

依田 修; 田村 直幸

Reports on Progress in Polymer Physics in Japan, 16, p.231 - 234, 1973/00

未焼成ポリテトラフルオルエチレンのラテラル方向の微結晶サイズと格子歪を、100デバイーシェラー線を測定することによって調べた。その結果(1)乳化重合PTFEに懸濁重合物よりも結晶サイズは大きく、また分子鎖のパッキングはより密である。(2)機械的処理によって微結晶はより小さくなり、格子歪は増大すると共に、非晶成分が現われる。(3)焼成によってポリマー分子鎖は再配列を起し、格子の欠陥部分は結晶外に押し出されることにより結晶サイズが増大すると共に歪は減少する。(4)50MRまでの線照射では結晶サイズ、格子歪共に顕著な変化は見出されないことがわかった。