X-Ray Elastic Constants for β-SiC and Residual Stress Anisotropy in a Hot-Pressed Al2O3/SiC(Whisker) Composite

1991 ◽  
pp. 643-650
Author(s):  
Paul Predecki ◽  
Alias Abuhasan ◽  
Charles S. Barrett
Keyword(s):  
Residual Stress ◽  
Elastic Constants ◽  
X Ray ◽  
Stress Anisotropy

Direct X-Ray Measurement of Residual Strains in Textured Steel

1983 ◽  
Vol 27 ◽  
pp. 197-206
Author(s):  
C. P. Gazzara
Keyword(s):  
Residual Stress ◽  
Crystal Lattice ◽  
Elastic Constants ◽  
Random Distribution ◽  
Elastic Anisotropy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Strains ◽  
Residual Stress Analysis ◽  
Textured Materials

One of the most detrimental effects on the accuracy of an X-ray diffraction residual stress analysis, XRDRSA(l), is found in the examination of textured materials. The degree of elastic anisotropy and texture is in general agreement with the extent of the error in the residual stress. Several approaches have been made to correct for the effects of texture, particularly involving experimental techniques. Reviews of such efforts are given by H. D811e(2), v.M. Hauk﹛3) and G. Maeder, J.L. Lebrun and J.M. Sprauel (4), just to mention a few.A brief chronology of the texture corrections involved in XRDRSA follows. With isotropic materials the d spacing of a crystal lattice, d, is assumed to vary linearly with sin2ψ. With textured materials the d vs sin2ψ relationship is nonlinear. This is due to the anisotropy of the elastic constants and their departure from a random distribution, or taking on a preferred orientation.

Determination of X-ray Elastic Constants in a Ti-14Al-21Nb Nb Alloy and a Ti-14Al-21Nb/SiC Metal Matrix Composite

1990 ◽  
Vol 34 ◽  
pp. 689-698 ◽  
Author(s):  
J. Jo ◽  
R. W. Hendricks ◽  
W. D. Brewer ◽  
Karen M. Brown
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Elastic Constant ◽  
Theoretical Calculation ◽  
Metal Matrix Composite ◽  
Elastic Constants ◽  
Metal Matrix ◽  
Intrinsic Value ◽  
X Ray

Residual stress values in a material are governed by the measurements of the atomic spacings in a specific crystallographic plane and the elastic constant for that plane. It has been reported that the value of the elastic constant depends on microstructure, preferred orientation, plastic deformation and morphology [1], Thus, the theoretical calculation of the elastic constant may deviate from the intrinsic value for a real alloy.

The Effects of X-Ray Optics on Residual Stress Measurements in Steel

1973 ◽  
Vol 17 ◽  
pp. 354-370 ◽  
Author(s):  
Chester F. Jatczak ◽  
Harald H. Boehm
Keyword(s):  
Residual Stress ◽  
Elastic Constants ◽  
Hardened Steel ◽  
Broad Line ◽  
Beam Optics ◽  
General Electric ◽  
X Ray ◽  
Stress Measurements ◽  
Accuracy And Precision ◽  
Peak Location

AbstractThe effects of various combinations of divergence, receiving and Soller slits on x-ray measurements were investigated for Siemens-Halske and General Electric diffractometers. Influences of the following factors which also affect accuracy and precision of x-ray R.S. results were determined in addition: (a) parafocus versus stationary detector focusing geometry, (b) method of peak location, (c) LPA intensity correction, (d) diffractometer electronic stability and (e) elastic constants.The optimum choiees of beam optics and factors (a-e) were defined with regard to aecuraey, precision and minimurn time for stress deterniination, on sharp and broad line speeimens of soft (annealed) and hardened steel and of annealed Cr-powder.

Residual Stress Measurement of Silicon Nitride and Silicon Carbide by X-Ray Diffraction Using Gaussian Curve Method

1988 ◽  
Vol 32 ◽  
pp. 459-469 ◽  
Author(s):  
Masanori Kurita ◽  
Ikuo Ihara ◽  
Nobuyuki Ono
Keyword(s):  
Residual Stress ◽  
Single Crystal ◽  
Elastic Constants ◽  
Stress Measurement ◽  
Polycrystalline Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Small Areas ◽  
Curve Method ◽  
The Continuum

The residual stress induced by grinding or some thermal treatment has a large effect on the strength of ceramics. The X-ray technique can be used to nondestructively measure the residual stress in small areas on the surface of polycrystalline materials. The X-ray stress measurement is based on. the continuum mechanics for macroscopically isotropic polycrystalline materials. In this method, the stress value is calculated selectively from strains of a particular diffraction plane in the grains which are favorably oriented for the diffraction. In general, however, the elastic constants of a single crystal depend on the plane of the lattice, since a single crystal is anisotropic, The behavior of the deformation of individual crystals in the aggregate of polycrystalline materials under applied stress has not yet been solved successfully. Therefore, the stress constant and elastic constants for a particular diffracting plane should be determined experimentally in order to determine the residual stress accurately by X-ray diffraction.

Pattern decomposition for residual stress analysis: a generalization taking into consideration elastic anisotropy and extension to higher-symmetry Laue classes

2017 ◽  
Vol 50 (4) ◽  
pp. 1011-1020 ◽  
Author(s):  
Peter Schoderböck ◽  
Peter Leibenguth ◽  
Michael Tkadletz
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Elastic Constants ◽  
Elastic Anisotropy ◽  
Hard Coatings ◽  
Titanium Carbonitride ◽  
X Ray ◽  
Residual Stress State ◽  
Pattern Decomposition ◽  
Decomposition Procedure

The residual stress state of ion-conducting layers (yttria stabilized zirconia) and protective hard coatings (α-aluminium oxide, titanium carbonitride) was investigated using X-ray diffraction techniques. Its evaluation within the tetragonal, trigonal and cubic phases present was performed by a whole powder pattern decomposition procedure according to Pawley. Going beyond previous work, the applied refinements directly include the influence of elastic anisotropy on the residual stress results. Starting from the single-crystal elastic coefficients, the X-ray elastic constants according to the Voigt and Reuss models were calculated. Finally, the Neerfeld–Hill model as a generalization was implemented to introduce thehkl-specific X-ray elastic constants for calculating the residual stress magnitude within the least-squares minimization routine. It was possible to resolve the residual stress state in stacked layers of different chemical and phase composition and to reproduce the results obtained by the classical χ- and ω-inclination sin2Ψ techniques.

Analysis of X-Ray Diffraction Data for the Characterization of Residual Stress

1991 ◽  
Vol 35 (A) ◽  
pp. 561-569
Author(s):  
Jun S. Park ◽  
James F. Shackelford
Keyword(s):  
Residual Stress ◽  
Elastic Constants ◽  
Diffraction Data ◽  
Stress Gradient ◽  
Bearing Steel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Angle ◽  
Stress States ◽  
Depth Ranges

AbstractThe analysis of linear dϕψ vs sin2ψ x-ray diffraction data in isotropic single phase materials was investigated for the evaluation of x-ray elastic constants. This study developed an experimental model for estimating x-ray elastic constants based on the analysis of biaxial residual stress states, A ball bearing steel and a 1018 steel weldment were evaluated.In a second study, the measurement of residual stress gradients was evaluated for those depth ranges mat can not be evaluated with a single radiation. This requires various planes and radiation energies to obtain the simultaneous conditions of high diffraction angle and large x-ray penetration depth. The evaluation of the overlapped stress gradient region is illustrated in terms of x-ray energy and diffraction angle for the ease of iron. This analysis is specifically developed for the purpose of stress gradient measurement using synchrotron radiation.

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