1
|
Ungár T, Ribárik G, Topping M, Jones RMA, Dan Xu X, Hulse R, Harte A, Tichy G, Race CP, Frankel P, Preuss M. Characterizing dislocation loops in irradiated polycrystalline Zr alloys by X-ray line profile analysis of powder diffraction patterns with satellites. J Appl Crystallogr 2021; 54:803-821. [PMID: 34188613 PMCID: PMC8202032 DOI: 10.1107/s1600576721002673] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 03/10/2021] [Indexed: 12/03/2022] Open
Abstract
This work extends the convolutional multiple whole profile (CMWP) line profile analysis (LPA) procedure to determine the total dislocation density and character of irradiation-induced dislocation loops in commercial polycrystalline Zr specimens. Zr alloys are widely used in the nuclear industry as fuel cladding materials in which irradiation-induced point defects evolve into dislocation loops. LPA has long been established as a powerful tool to determine the density and nature of lattice defects in plastically deformed materials. The CMWP LPA procedure is based on the Krivoglaz-Wilkens theory in which the dislocation structure is characterized by the total dislocation density ρ and the dislocation arrangement parameter M. In commercial Zr alloys irradiation-induced dislocation loops broaden the peak profiles, mainly in the tail regions, and occasionally generate small satellites next to the Bragg peaks. In this work, two challenges in powder diffraction patterns of irradiated Zr alloys are solved: (i) determination of the M values from the long tail regions of peaks has been made unequivocal and (ii) satellites have been fitted separately, using physically well established principles, in order to exclude them from the dislocation determination process. Referring to the theory of heterogeneous dislocation distributions, determination of the total dislocation density from the main peaks free of satellites has been justified. The dislocation loop structure has been characterized by the total dislocation density of loops and the M parameter correlated to the dipole character of dislocation loops. The extended CMWP procedure is applied to determine the total dislocation density, the dipole character of dislocation loops, and the fractions of 〈a〉- and 〈c〉-type loops in proton- or neutron-irradiated polycrystalline Zr alloys used in the nuclear energy industry.
Collapse
Affiliation(s)
- Tamás Ungár
- Materials Performance Centre, University of Manchester, Manchester M13 9PL, United Kingdom
- Department of Materials Physics, Eötvös University, PO Box 32, Budapest H-1518, Hungary
| | - Gábor Ribárik
- Department of Materials Physics, Eötvös University, PO Box 32, Budapest H-1518, Hungary
| | - Matthew Topping
- Materials Performance Centre, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Rebecca M. A. Jones
- Materials Performance Centre, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Xiao Dan Xu
- Materials Performance Centre, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Rory Hulse
- Materials Performance Centre, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Allan Harte
- Materials Performance Centre, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Géza Tichy
- Department of Materials Physics, Eötvös University, PO Box 32, Budapest H-1518, Hungary
| | - Christopher P. Race
- Materials Performance Centre, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Philipp Frankel
- Materials Performance Centre, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Michael Preuss
- Materials Performance Centre, University of Manchester, Manchester M13 9PL, United Kingdom
| |
Collapse
|
2
|
Modi MH, Gupta RK, Sinha M, Yadav PK. Influence of spin orbit splitting and satellite transitions on nickel soft X-ray optical properties near its L 2,3 absorption edge region. J Synchrotron Radiat 2020; 27:1633-1639. [PMID: 33147189 DOI: 10.1107/s1600577520011960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 08/31/2020] [Indexed: 06/11/2023]
Abstract
Transition elements exhibit strong correlations and configuration interactions between core and valence excited states, which give rise to different excitations inside materials. Nickel exhibits satellite features in its emission and absorption spectra. Effects of such transitions on the optical constants of nickel have not been reported earlier and the available database of Henke et al. does not represent such fine features. In this study, the optical behaviour of ion beam sputter deposited Ni thin film near the L2,3-edge region is investigated using reflection spectroscopy techniques, and distinct signatures of various transitions are observed. The soft X-ray reflectivity measurements in the 500-1500 eV photon energy region are performed using the soft X-ray reflectivity beamline at the Indus-2 synchrotron radiation source. Kramers-Kronig analysis of the measured reflectivity data exhibit features corresponding to spin orbital splitting and satellite transitions in the real and imaginary part of the refractive index (refraction and absorption spectra). Details of fine features observed in the optical spectra are discussed. To the best of our knowledge, this is the first study reporting fine features in the measured optical spectra of Ni near its L2,3-edge region.
Collapse
Affiliation(s)
- Mohammed H Modi
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, Maharashtra 400094, India
| | - Raj Kumar Gupta
- Soft X-ray Applications Laboratory, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013, India
| | - Mangalika Sinha
- Soft X-ray Applications Laboratory, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013, India
| | - Praveen Kumar Yadav
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, Maharashtra 400094, India
| |
Collapse
|
3
|
Abstract
A survey is given of a variety of effects that can arise in the scattering of electromagnetic waves from one- and two-dimensional randomly rough surfaces. The focus is primarily on multiple-scattering effects such as enhanced backscattering, enhanced transmission, satellite peaks, new features in speckle correlations and in second harmonic generation in reflection. Theoretical treatments of these phenomena are outlined, and experimental results illustrating them are presented.
Collapse
Affiliation(s)
- A A Maradudin
- Department of Physics and Astronomy, and Institute for Surface and Interface Science, University of California, Irvine 92697, USA
| | | |
Collapse
|