Establishment and Optimization of Angle Dispersive Neutron Diffraction Bulk Texture Measurement Environments

Abstract

Different from electron back-scattering diffraction and X-ray diffraction, neutron diffraction enables to directly measure the bulk texture because of the high penetrability and the large spot size of neutron beam and easily investigate the preferred orientation distributions of multiphase materials, coarse-grained materials and low symmetric materials including hexagonal metals, ceramics and rocks. In this paper, the texture measurement technical environments of two angle dispersive neutron diffractometers were established and optimized respectively, and their reliabilities were quantitatively examined through evaluating the bulk textures of a warm-pressed magnesium alloy and a multilayered multiphase steel sheet. It is found that the MUSASI-L neutron diffractometer with a single tube detector through selecting the proper collimation angle may achieve the similar texture evaluation reliability to the RESA-2 neutron diffractometer with one-dimensional position-sensitive detector, so that both of them are available to directly measure the bulk textures of various materials. In addition, the estimation of thermal neutron absorption shows that if a measurement error about 58% is acceptable, a cubic sample or a cylinder samples whose diameters is equal to its height may be employed to directly measure its bulk texture through completely bathing it in the well-collimated uniform neutron beam without doing the correction of neutron absorption anisotropy.

Evaluation of Residual Stress Relaxation in a Rolled Joint by Neutron Diffraction

“…Considering that only the macro strains and the macro stresses were investigated in this paper by using the limited experimental neutron diffraction data, the effect of texture-related potential intergranular strain on the residual stress [15] was omitted here and the early classic stress model was simply employed. However, such similar pioneering researches involving in the strain, stress and texture evaluation with a little higher uncertainty have an important promotive role to develop and upgrade the neutron diffraction stress and/or texture measurement techniques in Japan using the constant wavelength neutron source at Japan Research Reactor No.3 (JRR-3, Tokai, Japan) [23][24][25][26][27] and the spallation neutron source at Japan Proton Accelerator Research Complex (J-PARC, Tokai, Japan) [28][29][30]. Actually, the rapid texture measurement technique [29] and the simultaneous measurement technique of the phase fractions, the strain, the stress and the texture [30] have been well established using the BL20 (iMATERIA) and BL19 (TAKUMI) neutron diffractometers at J-PARC, respectively, which provide us wider accessibility to neutron diffraction techniques for accelerating the research and development activities of advanced engineering materials and related products [30], together with other domestic and oversea neutron diffraction facilities, for example, the diffractometer for residual stress analysis (RESA-1) at JRR-3, Japan [31,32] and the Residual Stress Neutron Diffractometer (RSND) at the China Mianyang Research Reactor (CMRR), Beijing, China) [33].…”

Progress in Bulk Texture Measurement Using Neutron Diffraction

“…In addition, the different X-ray target may also lead to some difference in the pole figure measurement because of different penetration depths into the sample underneath. For neutron diffraction, the above correction is not necessary if a measurement error about 5~8% is acceptable because of the cubic sample rotation induced absorption effect [6].…”

“…Because textures are modified by all kinds of orientation dependent physical processes during the material manufacture/preparation [1], the quantitative texture evaluation is an important academic field related to materials engineering. Different with the conventional X-ray diffraction and the electron backscattering diffraction, the neutron diffraction can directly measure the bulk textures of various materials and provide high statistical texture information for predicting the material anisotropic property because of the large beam spot and the high matter penetrability [2][3][4][5][6], and it is powerful to monitor in situ microstructure evolutions under various loading/temperature environments [7][8][9][10][11]. Considering the potential contribution to the engineering materials, JAEA upgraded two angle dispersive neutron diffractometers [6] and TAKUMI time-of-flight neutron diffractometer [12] to increase the accessibility and flexibility of neutron diffraction facilities for bulk texture evaluation.…”

High stereographic resolution texture and residual stress evaluation using time-of-flight neutron diffraction

“…For constant-wavelength (or angle-dispersive, AD) neutron diffraction (Bunge et al, 1982;Xu et al, 2008Xu et al, , 2012Hansen et al, 2008;Brokmeier et al, 2011;Zhang et al, 2011;Li et al, 2016), only a few low-Q diffraction peaks can be collected simultaneously depending on the stereographic angular coverage of the single-tube, one-dimensional or two-dimensional position-sensitive detector (PSD) panel. Here, Q is the momentum transfer, Q = 2sin K i = 4 sin / = 2/d, where 2 is the scattering angle, K i is the incident momentum, is the wavelength of the incident neutron beam and d is the lattice plane spacing, usually abbreviated as the d spacing.…”