Residual stress analysis of energy-dispersive diffraction data using a two-detector setup: Part I — Theoretical concept

2018 ◽  
Vol 877 ◽  
pp. 24-33 ◽  
Author(s):  
Daniel Apel ◽  
Matthias Meixner ◽  
Alexander Liehr ◽  
Manuela Klaus ◽  
Sebastian Degener ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Diffraction Data ◽  
Theoretical Concept ◽  
Energy Dispersive ◽  
Residual Stress Analysis ◽  
Energy Dispersive Diffraction

Residual Stress Analysis by Energy-Dispersive Synchrotron Diffraction: Concepts for High Resolution Depth Profiling in Real Space

2013 ◽  
Vol 768-769 ◽  
pp. 44-51 ◽  
Author(s):  
Tillman Fuß ◽  
Matthias Meixner ◽  
Manuela Klaus ◽  
Christoph Genzel
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Depth Profiling ◽  
Real Space ◽  
Energy Dispersive ◽  
Scanning Method ◽  
Gauge Volume ◽  
Inclination Angles ◽  
Residual Stress Analysis ◽  
Depth Gradients

Recently, the ‘stress scanning method’ has been introduced in the field of depth resolved residual stress analysis. The principle of this method is based on depth scans that are performed in several inclination angles with a gauge volume characterized by a height dimension in the range of 10 µm. This method has been used in the energy-dispersive mode of diffraction for rather long-range depth gradients. In this case the variation of the residual stresses is negligible on the scale of the gauge volume height dimension. In this contribution it is shown that the stress scanning method can be extended to the analysis of steep residual stress depth gradients that vary significantly even within the height dimension of the gauge volume, but a careful evaluation of the measured data is necessary and must be adapted to the special case.

Reassessment of evaluation methods for the analysis of near-surface residual stress fields using energy-dispersive diffraction

2019 ◽  
Vol 52 (1) ◽  
pp. 94-105 ◽  
Author(s):  
Manuela Klaus ◽  
Christoph Genzel
Keyword(s):  
Residual Stress ◽  
Single Crystal ◽  
Stress Analysis ◽  
Elastic Anisotropy ◽  
Evaluation Methods ◽  
Stress Factors ◽  
Energy Dispersive ◽  
Evaluation Procedure ◽  
X Ray ◽  
Energy Dispersive Diffraction

In this paper two evaluation methods for X-ray stress analysis by means of energy-dispersive diffraction are reassessed. Both are based on the sin2ψ measuring technique. Advantage is taken of the fact that the d ψ hkl –sin2ψ data obtained for the individual diffraction lines E hkl not only contain information about the depth and orientation dependence of the residual stresses, but also reflect the single-crystal elastic anisotropy of the material. With simulated examples, it is demonstrated that even steep residual stress gradients could be determined from sin2ψ measurements that are performed up to maximum tilt angles of about 45°, since the d ψ hkl –sin2ψ distributions remain almost linear within this ψ range. This leads to a significant reduction of the measuring effort and also makes more complex component geometries accessible for X-ray stress analysis. Applying the modified multi-wavelength plot method for data analysis, it turns out that a plot of the stress data obtained for each reflection hkl by linear regression versus the maximum information depth τψ=0 hkl results in a discrete depth distribution which coincides with the actual Laplace space stress depth profile σ(τ). The sensitivity of the residual stress depth profiles σ(τψ=0 hkl ) to the diffraction elastic constants ½S 2 hkl used in the sin2ψ analysis can be exploited to refine the grain-interaction model itself. With respect to the universal plot method the stress factors F ij which reflect the material's anisotropy on both the microscopic scale (single-crystal elastic anisotropy) and the macroscopic scale (anisotropy of the residual stress state) are used as driving forces to refine the strain-free lattice parameter a 0 during the evaluation procedure.

Improvements in Energy Dispersive Diffraction in Respect of Residual Stress Analysis

2008 ◽  
Vol 571-572 ◽  
pp. 189-195 ◽  
Author(s):  
Ingwer A. Denks ◽  
Christoph Genzel
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Energy Dispersive ◽  
Secondary Beam ◽  
Energy Position ◽  
Dead Time Correction ◽  
Incoming Beam ◽  
Time Correction ◽  
Reflection Geometry ◽  
Residual Stress Analysis

In residual stress analysis (RSA) using energy dispersive (ED) diffraction care has to be taken of the detector energy stability. For a given detector system it is demonstrated that the energy position decreases significantly with dead time. Correction of the RSA data both in reflection and scanning experiments allows a significant improvement in the reliability of RSA under different conditions. Owing the small diffraction angles in ED experiments, the effect of adjustment errors in reflection geometry is investigated revealing the need of a wide incoming beam combined with high collimation of the secondary beam. The differences in the used absorber materials are shown in respect of sample heating and beam widening due to diffuse scattering.

scholarly journals Energy-Dispersive Residual Stress Analysis under Laboratory Conditions: Concept for a New Type of Diffractometer

2014 ◽  
Vol 996 ◽  
pp. 192-196 ◽  
Author(s):  
Alexander Liehr ◽  
Manuela Klaus ◽  
Wolfgang Zinn ◽  
C. Genzel ◽  
Berthold Scholtes
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Evaluation Method ◽  
Diffraction Method ◽  
Energy Dispersive ◽  
Photon Flux ◽  
Surface Residual Stress ◽  
Near Surface ◽  
Laboratory Conditions ◽  
Residual Stress Analysis

In the past decade energy-dispersive (ED) synchrotron diffraction has evolved into a powerful tool for materials analysis. Recording complete diffraction patterns in rather few different measuring directions allows for depth-resolved analysis not only of the near-surface residual stress state, but also of composition and even texture gradients. However, since the number of synchrotron beamlines dedicated to ED-diffraction is restricted to very few instruments, alternatives have to be found which allow for ED residual stress analysis even under low flux laboratory conditions. In this project we start to establish the scientific basis for a measuring and evaluation method to make the transfer of the ED method to the laboratory dimensions possible, which is adapted to the conditions of much lower photon flux and larger beam divergences of laboratory X-ray sources. In this paper, we present the concept of an ED-diffractometer which is equipped with two detectors to enable simultaneous data acquisition for two orientations of the diffraction vector with respect to the sample reference system. The first constructive and experimental steps are presented and furthermore the possibilities and limitations of the new laboratory method and the advantages of the ED diffraction method to realize short measurement times in order to realize a high resolution of information depth are discussed.

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