Laue microdiffraction characterisation of as-cast and tensile deformed Al microwires

Abstract

Single-crystalline cast aluminium microwires with a diameter near 15 mm are characterised by Laue microdiffraction. A microwire in the as-cast condition exhibits a misorientation below 1 • over a length of 500 mm. The measured density of geometrically necessary dislocations is low, ,10 12 m −2 , though local maxima up to one order of magnitude higher are found. After tensile deformation to failure, the dislocation density is significantly increased in microwires that have mostly deformed in single slip (≈2 × 10 13 m −2), and yet higher when deformation has occurred by multiple slip (≈6 × 10 13 m −2). In deformed single slip oriented microwires, the streaking directions of Laue spots show that dislocations are stored (though not exclusively) on the primary slip system. Results are consistent with a deformation mechanism governed by rotating, likely singlearm, sources.

Processing Laue Microdiffraction Raster Scanning Patterns with Machine Learning Algorithms: A Case Study with a Fatigued Polycrystalline Sample

“…The rotation-free feature of Laue microdiffraction renders it suitable for in-situ or ex-situ mechanical experiments [17][18][19][20][21][22]. Nevertheless, considerable efforts have to be made to ensure the consistency of the illuminated volumes at the moments of image acquisition, e.g., either using the fiducial markers deposited to the sample surface [23], or resorting to the digital image correlation (DIC) code [24].…”

Indexing of superimposed Laue diffraction patterns using a dictionary–branch–bound approach

“…Laue diffraction occurs when a parallel broad-bandpass X-ray beam illuminates a crystalline sample. Indexing a Laue diffraction pattern allows the crystallographic orientation, and in certain cases lattice elastic strains and defects of the sample, to be determined (Sheremetyev et al, 1991;Marı ´n & Die ´guez, 1999;Maaß et al, 2006;Xu et al, 2017;Deillon et al, 2019). With the development of Laue microdiffraction, which utilizes a focused beam, nondestructive 3D characterization can be achieved with submicrometre spatial resolution (Larson et al, 2002;Larson & Levine, 2013;Hofmann et al, 2012;Cornelius & Thomas, 2018;O ¨rs et al, 2018;Altinkurt et al, 2018).…”