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Your search keyword '"C. Detlefs"' showing total 3 results
Start Over Author "C. Detlefs" Publisher elsevier
3 results on '"C. Detlefs"'

1. High-resolution 3D strain and orientation mapping within a grain of a directed energy deposition laser additively manufactured superalloy

Author

Y. Chen, Y.T. Tang, D.M. Collins, S.J. Clark, W. Ludwig, R. Rodriguez-Lamas, C. Detlefs, R.C. Reed, P.D. Lee, P.J. Withers, and C. Yildirim

Subjects
Mechanics of Materials, Mechanical Engineering, Metals and Alloys, General Materials Science, Condensed Matter Physics
Abstract

The industrialization of Laser Additive Manufacturing (LAM) is challenged by the undesirable microstructures and high residual stresses originating from the fast and complex solidification process. Non-destructive assessment of the mechanical performance controlling deformation patterning is therefore critical. Here, we use Dark Field X-ray Microscopy (DFXM) to map the 3D subsurface intragranular orientation and strain variations throughout a surface-breaking grain within a directed energy deposition nickel superalloy. DFXM results reveal a highly heterogenous 3D microstructure in terms of the local orientation and lattice strain. The grain comprises ≈ 5 µm-sized cells with alternating strain states, as high as 5 ×10−3 , and orientation differences

Published
2023
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2. Analytical transmission cross-coefficients for pink beam X-ray microscopy based on compound refractive lenses.

Author

Falch KV, Detlefs C, Snigirev A, and Mathiesen RH

Abstract

Analytical expressions for the transmission cross-coefficients for x-ray microscopes based on compound refractive lenses are derived based on Gaussian approximations of the source shape and energy spectrum. The effects of partial coherence, defocus, beam convergence, as well as lateral and longitudinal chromatic aberrations are accounted for and discussed. Taking the incoherent limit of the transmission cross-coefficients, a compact analytical expression for the modulation transfer function of the system is obtained, and the resulting point, line and edge spread functions are presented. Finally, analytical expressions for optimal numerical aperture, coherence ratio, and bandwidth are given., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Published
2018
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3. Zernike phase contrast in high-energy x-ray transmission microscopy based on refractive optics.

Author

Falch KV, Lyubomirsky M, Casari D, Snigirev A, Snigireva I, Detlefs C, Michiel MD, Lyatun I, and Mathiesen RH

Abstract

The current work represents the first implementation of Zernike phase contrast for compound refractive lens based x-ray microscopy, and also the first successful Zernike phase contrast experiment at photon energies above 12 keV. Phase contrast was achieved by fitting a compound refractive lens with a circular phase plate. The resolution is demonstrated to be sub-micron, and can be improved using already existing technology. The possibility of combining the technique with polychromatic radiation is considered, and a preliminary test experiment was performed with positive results., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Published
2018
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