Repeatability and sensitivity characterization of the far-field high-energy diffraction microscopy instrument at the Advanced Photon Source

Abstract

In the last two decades, far-field high-energy diffraction microscopy (FF-HEDM) and similar non-destructive techniques have been actively developed at synchrotron light sources around the world. As these techniques (and associated analysis tools) are becoming more available for the general users of these light sources, it is important and timely to characterize their performance and capabilities. In this work, the FF-HEDM instrument implemented at the 1-ID-E endstation of the Advanced Photon Source (APS) is summarized. The set of measurements conducted to characterize the instrument's repeatability and sensitivity to changes in grain orientation and position are also described. When an appropriate grain matching method is used, the FF-HEDM instrument's repeatability is approximately 5 µm in translation, 0.02° in rotation, and 2 × 10−4 in strain; the instrument sensitivity is approximately 5 µm in translation and 0.05° in rotation.

Using Powder Diffraction Patterns to Calibrate the Module Geometry of a Pixel Detector

“…Before the distortion correction, the eigenstrain values were (−13 × 10 −6 , −33 × 10 −6 , and 46 × 10 −6 ), and after correction, these were reduced to (9 × 10 −6 , 12 × 10 −6 , and −21 × 10 −6 ). These values for strains are an order of magnitude lower than the numbers typically obtained for monochromatic diffraction experiments [31,32] and closer to the numbers achieved using Laue-DIC methods [33,34]. This improvement may be due to the use of extremely fine angular slicing combined with excellent counting statistics but perhaps also due to the use of a deviatoric strain tensor that neglects the wavelength uncertainties.…”

Resolving intragranular stress fields in plastically deformed titanium using point-focused high-energy diffraction microscopy

“…However, with nf-HEDM, the elastic strain tensor cannot be easily measured (although exciting progress has been made toward these efforts recently [66,67]). The ff-HEDM orientation, spatial, and strain resolutions are approximately 0.02°, 5 μm, and 2 × 10 −4 , respectively [68], and the nf-HEDM orientation and spatial resolution are approximately 0.1° and 1 − 2 μm, respectively [6,69,70]. Ff-HEDM and nf-HEDM are performed using a "box" beam [16,62,71,72] or a vertically focused "line" beam [62,64,65] wherein the entire width of the cross-section of a sample is illuminated.…”

Rapid detection of rare events from in situ X-ray diffraction data using machine learning

“…Details of the FF-HEDM instrument geometry (Fig. 4) are given by Park et al (2021). The main features are as follows:…”

“…In particular, highenergy diffraction microscopy (HEDM) can extract 3D microstructure information and grain-resolved attributes; it can also track their evolution when combined with in situ thermo-mechanical loading capabilities (Lienert et al, 2011;Schuren et al, 2015;Naragani et al, 2017). The far-field HEDM (FF-HEDM) variant (Bernier et al, 2020;Park et al, 2021) can provide the center of mass, crystallographic orientation and elastic strain tensor for each constituent grain in a polycrystalline aggregate. These FF-HEDM measurements are often combined with other measurement modalities such as near-field HEDM and tomography to fully understand the microstructure and state and their evolution in a polycrystalline material (Suter et al, 2008;Turner et al, 2017;Naragani et al, 2017;Sangid et al, 2020).…”