Depth dependence of elastic grain interaction and mechanical stress: Analysis by x-ray diffraction measurements at fixed penetration/information depths

2006 ◽  
Vol 100 (11) ◽  
pp. 114904 ◽  
Author(s):  
A. Kumar ◽  
U. Welzel ◽  
E. J. Mittemeijer
Keyword(s):  
Stress Analysis ◽  
Mechanical Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Depth Dependence ◽  
Grain Interaction

scholarly journals Residual stress and strain-free lattice-parameter depth profiles in a γ′-Fe4N1-x layer on an α-Fe substrate measured by x-ray diffraction stress analysis at constant information depth

2009 ◽  
Vol 24 (4) ◽  
pp. 1342-1352 ◽  
Author(s):  
M. Wohlschlögel ◽  
U. Welzel ◽  
E.J. Mittemeijer
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Depth Profile ◽  
Nitrogen Concentration ◽  
Lattice Parameter ◽  
Free Lattice ◽  
X Ray Diffraction ◽  
X Ray ◽  
Depth Profiles ◽  
Grain Interaction

The residual stress and lattice-parameter depth profiles in a γ′-Fe4N1-x layer (6-μm thickness) grown on top of an α-Fe substrate were investigated using x-ray diffraction stress analysis at constant penetration depths. Three different reflections (220, 311, and 222) were recorded at six different penetration depths using three different wavelengths. At each penetration depth, x-ray diffraction stress analysis was performed on the basis of the sin2ψ method. As a result, the residual-stress depth profile was obtained from the measured lattice strains. The lattice spacings measured in the strain-free direction were used to determine the (strain-free) lattice-parameter depth profile. The nitrogen-concentration depth profile in the layer was calculated by applying a relationship between the (strain-free) γ′ lattice parameter and the nitrogen concentration. It was found that the strain-free lattice-parameter depth profile as derived from the 311 reflections is best compatible with nitrogen concentrations at the surface and at the γ′/α interface as predicted on the basis of local thermodynamic equilibrium. It could be shown that the 311 reflection is most suitable for the analysis of lattice-parameter and residual stress depth profiles because the corresponding x-ray elastic constants exhibit the least sensitivity to the type of and changes in grain interaction. The depth-dependence of the grain interaction could be revealed. It was found that the grain interaction changes from Voigt-type near the surface to Reuss-type at the layer/substrate interface.

scholarly journals Problem of elastic anisotropy and stacking faults in stress analysis using multireflection grazing-incidence X-ray diffraction

2015 ◽  
Vol 48 (2) ◽  
pp. 492-509 ◽  
Author(s):  
Marianna Marciszko ◽  
Andrzej Baczmański ◽  
Mirosław Wróbel ◽  
Wilfrid Seiler ◽  
Chedly Braham ◽  
...  
Keyword(s):  
Tensile Test ◽  
Stress Analysis ◽  
Elastic Anisotropy ◽  
Stacking Faults ◽  
Interaction Model ◽  
Grazing Incidence ◽  
Stress Factors ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Interaction

Multireflection grazing-incidence X-ray diffraction (MGIXD) was used to determine the stress- and strain-free lattice parameter in the surface layer of mechanically treated (polished and ground) tungsten and austenitic steel. It was shown that reliable diffraction stress analysis is possible only when an appropriate grain interaction model is applied to an anisotropic sample. Therefore, verification of the X-ray stress factors (XSFs) was accomplished by measuring relative lattice strains during anin situtensile test. The results obtained using the MGIXD and standard methods (χ and ω geometries) show that the Reuss and free-surface grain interaction models agree with the experimental data. Moreover, a new interpretation of the MGIXD results was proposed and applied for the first time to measure the probability of stacking faults as a function of penetration depth for a polished and ground austenitic sample. The XSF models verified in the tensile test were used in the analysis of residual stress components.

Diffraction stress analysis of elastic grain interaction in polycrystalline materials

2007 ◽  
Vol 222 (3-4) ◽  
Author(s):  
Udo Welzel ◽  
Eric J. Mittemeijer
Keyword(s):  
Stress Analysis ◽  
Mechanical Behaviour ◽  
Classical Field ◽  
Polycrystalline Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Interaction ◽  
Polycrystalline Solids ◽  
Solid Bodies ◽  
Recent Insight

Recent insight on the elastic grain interaction in polycrystalline solids has been summarized. A breakthrough in this classical field of mechanical behaviour of solid bodies is due to highly accurate (X-ray) diffraction stress analysis. The occurrence of so-called direction-dependent grain interaction,

scholarly journals Формирование и трансформация моноклинной и орторомбической фаз в реакторных порошках сверхвысокомолекулярного полиэтилена

2018 ◽  
Vol 60 (9) ◽  
pp. 1847
Author(s):  
М.В. Байдакова ◽  
П.В. Дороватовский ◽  
Я.В. Зубавичус ◽  
Е.М. Иванькова ◽  
С.С. Иванчев ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Room Temperature ◽  
Monoclinic Phase ◽  
Orthorhombic Phase ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Polymer Synthesis ◽  
X Ray Diffraction ◽  
Reactor Powder ◽  
X Ray ◽  
The One

AbstractUsing powerful synchrotron X-ray radiation of the beamline “Belok” operated by the National Research Center “Kurchatov Institute,” we perform X-ray diffraction (XRD) study of an intact, virgin (not subjected to any external mechanical loads) particle isolated from reactor powder of ultrahigh molecular weight polyethylene. Along with the peaks originating from the orthorhombic phase, we detect the peaks characteristic of the monoclinic phase that is stable only under mechanical stress, suggesting that the mechanical stress that leads to the formation of the monoclinic phase and persists at room temperature develops during the polymer synthesis. The monoclinic phase gradually disappears when the particle is heated stepwise in increments of 5 K, and its peaks become undetectable when the temperature reaches 340 K. We contrast the results obtained for the phase composition of the virgin particle to those for a tablet prepared by compaction of the same reactor powder at room temperature. XRD analyses of the tablet were performed on D2 Phaser (Bruker) instrument. The monoclinic phase that originates during the polymer synthesis and the one that forms in the tablet during compaction have different parameters. We discuss the mechanisms by which these two different monoclinic phases originate during the processes involved.

Statistical Errors in X-Ray Triaxial Stress Analysis by Cos α Method

2021 ◽  
Vol 1016 ◽  
pp. 423-428
Author(s):  
Shoichi Ejiri ◽  
Hiroaki Ohba ◽  
Toshihiko Sasaki
Keyword(s):  
Stress State ◽  
Stress Analysis ◽  
Measurement Theory ◽  
Triaxial Stress ◽  
X Ray Diffraction ◽  
New Techniques ◽  
X Ray ◽  
Statistical Errors ◽  
Residual Stress State ◽  
Metal Materials

Currently, the sin2ψ method is established as an effective technique as how to measure the residual stress state of metal materials non-destructively by X-ray diffraction. In recent years, new X-ray stress measurements with two-dimensional detector are developed and spreading in the world. There is the cosα method as one of the new techniques. However, the research about the statistical errors in the method continues. The measurement theory of the cos α method is reviewed on the triaxial stress state. The triaxial stress analysis by the method is examined and discussed from a viewpoint of the derived errors for the determination.

scholarly journals The Stability of Icosahedral Cd-Yb

2003 ◽  
Vol 805 ◽  
Author(s):  
Günter Krauss ◽  
Sofia Deloudi ◽  
Andrea Steiner ◽  
Walter Steurer ◽  
Amy R. Ross ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ambient Temperature ◽  
Mechanical Stress ◽  
Single Crystals ◽  
High Temperatures ◽  
Low Temperatures ◽  
Ambient Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Stability

ABSTRACTThe stability of single-crystalline icosahedral Cd-Yb was investigated using X-ray diffraction methods in the temperature range 20 K ≤ T ≤ 900 K at ambient pressure and from ambient temperature to 873 K at about 9 GPa. Single-crystals remain stable at low temperatures and in the investigated HP-HT-regime. At high temperatures and ambient pressure, the quasicrystal decomposes. The application of mechanical stress at low temperatures yields to the same decomposition, the formation of Cd. A reaction of icosahedral Cd-Yb with traces of oxygen or water causing the decomposition seems reasonable, but a low-temperature instability of this binary quasi-crystal cannot be ruled out totally.

Sign in / Sign up

Export Citation Format

Share Document