A Computer Technique for Rapid Decomposition of X-Ray Diffraction Instrumental Aberrations from Mineral Line Profiles

2015 ◽  
pp. 155-171
Author(s):  
R. C. Jones ◽  
H. U. Malik
Keyword(s):  
Line Profiles ◽  
X Ray Diffraction ◽  
Computer Technique ◽  
X Ray ◽  
Rapid Decomposition

scholarly journals Fingerprinting shock-induced deformations via diffraction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Avanish Mishra ◽  
Cody Kunka ◽  
Marco J. Echeverria ◽  
Rémi Dingreville ◽  
Avinash M. Dongare
Keyword(s):  
High Speed ◽  
Shock Loading ◽  
Dislocation Slip ◽  
Line Profiles ◽  
X Ray Diffraction ◽  
Final State ◽  
X Ray ◽  
Shock Testing ◽  
Local Pressures ◽  
Deformation Modes

AbstractDuring the various stages of shock loading, many transient modes of deformation can activate and deactivate to affect the final state of a material. In order to fundamentally understand and optimize a shock response, researchers seek the ability to probe these modes in real-time and measure the microstructural evolutions with nanoscale resolution. Neither post-mortem analysis on recovered samples nor continuum-based methods during shock testing meet both requirements. High-speed diffraction offers a solution, but the interpretation of diffractograms suffers numerous debates and uncertainties. By atomistically simulating the shock, X-ray diffraction, and electron diffraction of three representative BCC and FCC metallic systems, we systematically isolated the characteristic fingerprints of salient deformation modes, such as dislocation slip (stacking faults), deformation twinning, and phase transformation as observed in experimental diffractograms. This study demonstrates how to use simulated diffractograms to connect the contributions from concurrent deformation modes to the evolutions of both 1D line profiles and 2D patterns for diffractograms from single crystals. Harnessing these fingerprints alongside information on local pressures and plasticity contributions facilitate the interpretation of shock experiments with cutting-edge resolution in both space and time.

Correction for errors in microstrain values from X-ray diffraction line profiles

1977 ◽  
Vol 36 (5) ◽  
pp. 1261-1264 ◽  
Author(s):  
H. De Keijser ◽  
E. J. Mittemeijer
Keyword(s):  
Diffraction Line ◽  
Line Profiles ◽  
X Ray Diffraction ◽  
X Ray

Real-time microstructure of shock-compressed single crystals from X-ray diffraction line profiles

2011 ◽  
Vol 44 (3) ◽  
pp. 574-584 ◽  
Author(s):  
Stefan J. Turneaure ◽  
Y. M. Gupta
Keyword(s):  
Single Crystals ◽  
Real Time ◽  
Line Profile ◽  
Distribution Model ◽  
Line Profiles ◽  
X Ray Diffraction ◽  
Multiple Diffraction ◽  
Heterogeneous Distribution ◽  
X Ray ◽  
Experimental Geometry

Methods to obtain and analyze high-resolution real-time X-ray diffraction (XRD) measurements from shock-compressed single crystals are presented. Procedures for extracting microstructural information – the focus of this work – from XRD line profiles are described. To obtain quantitative results, careful consideration of the experimental geometry is needed, including the single-crystal nature of the sample and the removal of instrumental broadening. These issues are discussed in detail. Williamson–Hall (WH) and profile synthesis (PS) analysis procedures are presented. More accurate than WH, the PS procedure relies on a forward calculation in which a line profile is synthesized by convoluting the instrumental line profile with a line profile determined from a diffraction simulation. The diffraction simulation uses the actual experimental geometry and a model microstructure for the shocked crystal. The shocked-crystal microstructural parameters were determined by optimizing the match between the synthesized and measured line profiles. XRD measurements on an Al crystal, shocked along [100] to 7.1 GPa using plate-impact loading, are used to demonstrate the WH and PS analysis methods. In the present analysis, the microstructural line broadening arises because of a distribution of longitudinal elastic microstrains. The WH analysis resulted in FWHM longitudinal microstrain distributions of 0.22 and 0.38% for Lorentzian and Gaussian line shape assumptions, respectively. The optimal FWHM longitudinal microstrain for the PS method was 0.35% with a pseudo-Voigt distribution (40% Lorentzian–60% Gaussian). The line profile measurements and PS analysis presented in this work provide new insight into the heterogeneous distribution of elastic strains in crystals undergoing elastic–plastic deformation during shock compression. Such microstrain distribution measurements are complementary to continuum measurements, which represent averages of the heterogeneous strains or stresses. The PS analysis is a general method capable of incorporating microstructural models more complex than the microstrain distribution model used in this work. As a next step, the PS method will be applied to line profiles of multiple diffraction peaks to separate strain- and size-broadening effects in shocked crystals.

In-Situ Studies of X-Ray Diffraction Line Profiles from Strained Copper Foils

2001 ◽  
Vol 378-381 ◽  
pp. 254-261 ◽  
Author(s):  
Robert W. Cheary ◽  
C.C. Tang ◽  
P.A. Lynch ◽  
M.A. Roberts ◽  
S.M. Clark
Keyword(s):  
Diffraction Line ◽  
Line Profiles ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Studies ◽  
Copper Foils
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