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Materialforschungsdiffraktometer zur Untersuchung von Eigenspannungen und Texturen

Materials Science Diffractometer for Residual Stress and Texture Analysis

- Beamline for Energy Dispersive Diffraction (EDDI) -

The HZB experiment EDDI at BESSY

Welcome

This page is supposed to inform about the activities at the EDDI beamline and give an outline of its characteristics to our users. Industrial customers will be informed about our service in "Service for Industry".

• Introduction
• Beamline Optical Lay-out
• Beamline Performance Data
• Diffractometer Setup
• Controlling and Data Acquisition
• Support at Experimental Station
• First Experiments
• Other Activities: ETA-Diffractometer
• Service for Industry (101 kB) (German version)
• Publications

Introduction

Since residual stresses are well-known to influence the mechanical properties of technical components to a large extend, the knowledge of their magnitude as well as distribution over the sample cross-section is of great practical interest. Whereas angle dispersive x-ray and neutron diffraction methods are used for non-destructive residual stress-, texture- and microstructure analysis at the surface and in the volume of the material, respectively, the application of energy dispersive diffraction in reflection geometry using white synchrotron radiation between about 10 and 100 keV offers new possibilities for such evaluations in the intermediate region up to depths of some hundred microns. The experimental station for energy dispersive diffraction (EDDI) at the 7T wiggler is devoted to such studies.

Beamline Optical Lay-out

The synchrotron beam generated by the 7T-Wiggler is devided into a monochromatic and a white beam. The former is used for the magnetic and the small angle scattering experiment, the latter for the EDDI experiment.The general layout of the two beamlines is shown in the following figure.

Photos of the optics hutch: upstream view, downstream view

The white beam passes a nearly 30 m evacuated pipe and a few optical components up to the place of the experiment. A mask limits the beam diameter to make sure it will not touch the pipe under any circumstances. Slits and filter system provide the experimenter with the beam characteristics required. A quick photon shutter allows defined and short exposure times of the sample.

Beamline Performance Data

The beamline is located at the most powerful insertion device at Bessy and thus provides excellent flux for energies from 10 to 80 keV. Even beyond 80 keV up to 150 keV the flux may be sufficient for many experiments as first experiments show.

Fig. 1: Calculation of flux and comparison to other possible sources

Investigations in respect of penetration depth have been made for a Ni-base alloy. In transmission, a 15 mm thick part gave reasonable diffraction patterns. The corresponding diagrams are shown in section first experiments.

The maximum beam cross section at the experimtent is 4 mm x 4 mm, given by the region of fairly homogeneous intensity (also in first experiments).

The vertical beam divergence is given by the size of the source (25 µm), the source to experiment distance (30 m) and the S2 slit gap. So the divergence at a maximum slit gap of 4 mm is 0.13 mrad which is even smaller than the natural vertical beam divergence of 0.3 mrad.

Diffractometer Setup

The diffractometer is designed by Seifert for the HZB experimental station at Bessy. Since the monochromatic beam of the adjacent experiment is passing in some 300 mm distance to the diffractometer center there have been some demands on the design of the positioning system. Consequently, the 5-axes positioner just allows the chi tilt in one direction, calling for a phi rotation of 180°, if both directions need to be analyzed. A 4-axes positioner is available for heavy parts up to 50 kg. Mind that it is not useable for all applications due to its limited flexibility.

photos: diffractometer side view and zoom up of optical components
technical reference: 5-axes positioner: front, side and top view
technical reference: 4-axes positioner: front, side and top view

Users who bring their own apparatus please consider the sample holder geometry.

technical reference: sample holder plate

Where applicable refer to the hardware limits interconnections.

Controlling and Data Acquisition

Beamline components and electronics (schematic)

For instrument control and data acquisition we use spec, which is a UNIX-based software package widely used for X-ray diffraction at synchrotrons (for details see http://www.certif.com).

The ASCII data file usually contains beamline data (beam current), all diffractometer data (motor positions) as well as various detector data (counts per channel, calibration data, acquisition time). For individual applications additional data, such as temperature and pressure, may be collected by means of the Keithley digital multimeter 2700. For detailed information about the Keithley see http://www.keithley.de.

A handout containing all basic spec commands for our application is available for download (108 kB).

Support

Infrastructure at Experimental Station

Available Software (Linux)

Available Software (Windows)

First Experiments

To get an impression of the beam characteristics we varied the scattering angle in the reflection mode from 10° to 2.5° and monitored the diffractograms. Due to the E=1/sin(2θ) relation, all peaks are shifted to higher energies. Regarding the well formed 111 reflection of a Ni-base alloy IN718, interpretation up to 150 keV is possible. At that time, the wiggler magnetic field was 6 T.

Changing to the transmission mode, we made some penetration studies by bringing different amounts of the same TiN coated steel sample into the beam. Though these experiments have also been taken place at 6 T, the penetration is remarkable. At diffraction angles of 6° reasonable diffractograms can be taken from a 15 mm piece within a view minutes.

For characterization of the beam cross section we translated a 100 µm Fe wire through the beam and monitored the diffraction peaks at low angles. Due to the beam limitation by the mask, the intensity stays fairly stable within about 4 mm and decreases rapidly to both sides.

Other Activities: ETA-Diffractometer

The figure below shows a schematic view of the diffractometer. It operates on the principle of the SEIFERT theta-theta-diffractometer MZ VI. In its basic configuration, the sample is aligned in a horizontal position, whereas both, the X-ray tube and the detector can be rotated in the vertical diffraction plane. Thus, working in this mode corresponds to the conventional omega-geometry as defined in the XSA. All sample rotations are based on a second 1-circle-goniometer which operates in the horizontal plane, i.e. its axis phi1 and the theta’/theta-axes are perpendicular to each other. The angle psi between the surface normal and g(hkl) is adjusted by means of an Eulerian cradle segment operating in an angular range between 0 and 90°, which is placed on the phi1-goniometer in such a way, that the psi- and the phi1-axis enclose an angle of 90°.

A rotation around phi1 exactly corresponds to the sample rotation around the scattering vector g(hkl) which is inclined by the angle psi against the surface normal. The azimuth phi of g(hkl) with respect to the sample system is adjusted by a rotation table phi2 inside the Eulerian cradle segment. From a generalised point of view, the ETA-diffractometer is a 5-circle diffractometer, which differs from a conventional 4-circle Eulerian cradle by the additional axis phi1 for the rotation of the cradle (segment) perpendicular to the θ’/θ-axes. This phi1-axis, however, is the necessary additional degree of freedom, which is needed for the direct realisation of the eta-rotation. For thin film stress analysis at grazing incidence, a variety of optical elements like soller slits and primary or secondary monochromators can be placed into both, the incident and the diffracted beam, respectively. The sample positioning is performed by means of x-, y- and z-translation tables and will be controlled by a system consisting of a laser and a CCD-camera which are focused on the centre of the diffractometer defined by the intersection of all rotation axes.

The photograph below shows the ETA-diffractometer setup in our lab. The table aside gives an overview of all common diffraction methods realized on the ETA-diffractometer.

Publications

Genzel, Ch., Genzel, A.:
Shear Stress Distribution in Crystals Induced by Mechanical Surface Load.
phys. stat. sol. (a) 117 (1990), 141 - 154.

Genzel, Ch., Reimers, W., Schwarz, O., Grosch, J.:
Development of the Residual Stress State in Case-Hardened Steels due to Austenite Transformation by Deep Cooling.
In: V. Hauk, H. P. Hougardy, E. Macherauch, H.-D. Tietz (Hrsg.): Residual Stresses. DGM-Informationsgesellschaft, Oberursel (1993), 129 - 138.

Schwarz, O., Grosch, J., Genzel, Ch., Reimers, W.:
Gefüge und Eigenspannungen tiefgekühlter und angelassener einsatzgehärteter Stähle.
Härterei-Techn. Mitt. 49 (1994), 134 - 141.

Genzel, Ch.:
Formalism for the Evaluation of Strongly Non-Linear Surface Stress Fields by X-Ray Diffraction in the Scattering Vector Mode.
phys. stat. sol. (a) 146 (1994), 629 - 637.

Genzel, Ch., Reimers, W., Schwarz, O., Grosch, J.:
Eigenspannungsentwicklung in einsatzgehärteten Stählen.
Härterei-Techn. Mitt. 50 (1995), 163 - 167.

Genzel, Ch., Reimers, W., Malek, R., Pöhlandt, K.:
Neutron and X-Ray Residual Stress Analysis of Steel Parts Produced by Cold Forward Extrusion and Tube Drawing.
Mat. Sci. Eng. A 205 (1996), 79 - 90.

Genzel, Ch.:
Evaluation of Stress Gradients *ij(z) from Their Discrete Laplace Transforms *ij(*k) Obtained by X-Ray Diffraction Performed in the Scattered Vector Mode.
phys. stat. sol. (a) 156 (1996), 353 - 363.

Pyzalla, A., Genzel, Ch., Reimers, W.:
Thermal residual microstresses in steel - NbC particulate composites studied by X-ray and neutron diffraction.
Mat. Sci. Eng. A 212 (1996), 130 - 138.

Pyzalla, A., Genzel, Ch., Reimers, W., Pöhlandt, K.:
Zerstörungsfreie Eigenspannungsanalyse im Inneren von Kaltmassivumformteilen.
Metall 50 (1996), 787 - 791.

Genzel, Ch.:
X-Ray Stress Gradient Analysis in Thin Layers - Problems and Attempts at Their Solution.
phys. stat. sol. (a) 159 (1997), 283 - 296.

Genzel, Ch.:
Line broadening by non-oriented micro residual stresses.
in: V. Hauk, Structural and Residual Stress Analysis by Nondestructive Methods. Elsevier, Amsterdam usw. 1997, 435 - 460.

Genzel, Ch.:
The scattering vector method.
in: V. Hauk, Structural and Residual Stress Analysis by Nondestructive Methods. Elsevier, Amsterdam usw. 1997, 384 - 387.

Genzel, Ch.:
A Study of X-Ray Residual Stress Gradient Analysis in Thin Layers with Strong Fibre Texture - I. Evaluation of the Stress Factors Fij.
phys. stat. sol. (a) 165 (1998), 347 - 360.

Genzel, Ch., Reimers, W.:
A Study of X-Ray Residual Stress Gradient Analysis in Thin Layers with Strong Fibre Texture - II. Examples.
phys. stat. sol. (a) 167 (1998), 751 - 762.

Genzel, Ch., Reimers, W.:
Some New Aspects in X-Ray Stress Analysis of Thin Layers.
Surface and Coatings Technology, 116–119 (1999), 404 - 409.

Genzel, Ch.:
A Self-Consistent Method for X-Ray Diffraction Analysis of Multiaxial Residual Stress Fields in the Near Surface Region of Polycrystalline Materials. I. Theoretical Concept.
J. Appl. Cryst., 32 (1999), 770 - 778.

Genzel, Ch., Broda, M., Dantz, D., Reimers, W.:
A Self-Consistent Method for X-Ray Diffraction Analysis of Multiaxial Residual Stress Fields in the Near Surface Region of Polycrystalline Materials. II. Examples.
J. Appl. Cryst., 32 (1999), 779 - 787.

Wroblewski, T., Claus, O., Crostack, H.- A., Fandrich, F., Genzel, Ch., Hradil, K., Ternes, W., Woldt, E.:
The New Diffractometer for Materials Science and Imaging at HASYLAB Beamline G3.
Nucl. Instrum. Meth. A 428 (1999), 570 - 582.

Dantz, D. Genzel, Ch., Reimers, W.:
Analysis of Macro and Micro Residual Stresses in Functionally Graded Materials by Diffraction Methods.
Mat. Sci. Forum, 308-311 (1999), 829 - 836.

Dantz, D. Genzel, Ch., Reimers, W., Weber, U., Schmauder, S:
Analyse von Makro- und Mikroeigenspannungen in Gradientenwerkstoffen (FGM).
in: K. Schulte, K. U. Kainer (Hrsg.) Verbundwerkstoffe und Werkstoffverbunde., Wiley-VCH, Weinheim usw., 1999, S. 704-709.

Genzel, Ch., Reimers, W.:
X-Ray Residual Stress Gradient Analysis Under Difficult Conditions - Attempts for Improving the Solution.
Mat. Sci. Forum, 321-324 (2000), 75 - 80.

Genzel, Ch.:
Entwicklung eines Mess- und Auswerteverfahrens zur röntgenographischen Analyse des Eigenspannungszustandes im Oberflächenbereich vielkristalliner Werkstoffe.
Habilitationsschrift, Humboldt-Universität Berlin, 2000.

Genzel, Ch., Stock, C., Wallis, B., Reimers, W.:
The Application of White Radiation to Residual Stress Analysis in the Intermediate Zone between Surface and Volume.
Nucl. Instrum. Meth. A 467 – 468 (2001), 1253 – 1256.

Haase, A., Genzel, Ch., Dantz, D., Löhmann, M., Wallis, B., Stock, C., Reimers, W.:
A new X-ray Diffractometer ‘ETA’ for Surface Gradient Investigations in Phase, Texture and Stress Analysis.
Applied Crystallography, Proc. of the XVIII Conference, Wisla, Poland, 04.-07.09.2000. World Scientific Publishing Co. Pte. Ltd., 2001, S. 97 – 100.

Goebel, Th., Menzel, S., Hecker, M., Brückner, W., Wetzig, K, Genzel, Ch.:
Stress Measurement in Thermal Loaded (Ti,Al)N Hard Coatings.
Surface and Coatings Technology 142–144 (2001), 861 - 867.

Genzel, Ch.:
X-Ray Stress Analysis in Presence of Gradients and Texture.
Adv. X-Ray Analysis 44 (2001), 247 – 256.

Lengsfeld, P., Nickel, N. H., Genzel, Ch., Fuhs, W.:
Stress in undoped and doped laser crystallized silicon,
J. Appl. Phys. 91 (2002), 9128 - 9135.

Stock, C., Genzel, Ch., Reimers, W.:
Problems Related to Energy-Dispersive X-Ray Stress Analysis Performed in Reflection Geometry.
Mat. Science Forum 404 - 407 (2002), 13 – 18.

Lengsfeld, P., Brehme, S., Brendel, K., Genzel, Ch., Nickel, N. H.:
Raman spectroscopy of heavily doped polycrystalline and microcrystalline silicon.
phys. stat. sol. (b) 235 (2003), 170 – 178.

Genzel, Ch., Reimers, W.:
Depth-resolved X-ray residual stress analysis in PVD (Ti,Cr)N hard coatings.
Z. Metallkd. 94 (2003), 655 – 661.

Genzel, Ch.:
Problems Related to X-ray Stress Analysis in Thin Films in the Presence of Gradients and Texture.
in: E. J. Mittemeijer, P. Scardi (Eds.), Diffraction Analysis of the Microstructure of Materials. Springer Series in Materials Science, Volume 68, 2004, p. 473 – 503.

Genzel, Ch., Stock, C., Reimers, W.:
Application of energy-dispersive diffraction to the analysis of multiaxial residual stress fields in the intermediate zone between surface and volume.
Mat. Sci. Eng. A 372 (2004), 28 – 43.

Panckow, A. N., Sladkov, D., Singh, P. K., Genzel, Ch.:
Low-temperature metal ion implantation assisted deposition of hard coatings.
Surface and Coatings Technology 188 - 189 (2004), 214 - 219.

Genzel, Ch.:
Diffraction Stress Analysis in Thin Films and Coatings – Problems, Methods and Perspectives.
J. of Neutron Research 12 (2004), 233 - 241.

Birkholz, M., Genzel, Ch., Jung. T.:
X-ray diffraction study of residual stress and preferred orientation in thin titanium films subjected to a high ion flux during deposition.
J. Appl. Phys. 96 (2004), 7202 - 7211.

Genzel, Ch., Klaus, M., Denks, I., Wulz, H.-G.:
Residual stress fields in surface-treated silicon carbide for space industry – comparison of biaxial and triaxial analysis using different X-ray methods
Mat. Sci. Eng. A 390 (2005), 376 - 384.

Genzel, Ch.:
X-Ray Residual Stress Analysis in Thin Films under Grazing Incidence – Basic Aspects and Applications.
Mat. Sciences and Technol. 21 (2005), 10 - 18.

I.A. Denks, M. Klaus, Ch. Genzel: "Determination of real space residual stress distributions sij(z) of surface treated materials with diffraction methods. Part II: Energy dispersive approach", in: Mater. Sci. Forum 524-525(2006), S. 37-42

Ch. Genzel, M. Klaus, I.A. Denks, H.-G. Wulz: "Residual stress fields in surface-treated silicon carbide for space industry – comparison of biaxial and triaxial analysis using different X-ray methods", in: Mater. Sci. Eng. A 390(2005), S. 376-384

M. Klaus, I.A. Denks, Ch. Genzel: "X-Ray Diffraction Analysis of Nonuniform Residual Stress Fields sigmaij(tau) under ifficult Conditions", in: Mater. Sci. Forum 524-525(2006), S. 601-606

Ch. Genzel, I.A. Denks, M. Klaus: "The Materials Science Beamline EDDI for Energy-Dispersive Analysis of Subsurface Residual Stress Gradients", in: Mater. Sci. Forum 524-525(2006), S. 193-198

I. M. Kötschau, H. Rodriguez-Alvarez, C. Streeck, A. Weber, M. Klaus, I.A. Denks, J. Gibmeier, Ch. Genzel, H.W. Schock: "Pressure Dependent Rapid Thermal Processing of CuInS2 Thin Films investigated by in-situ Energy Disper-sive X-Ray Diffraction" , in: Proceedings of the MRS Spring Meeting 2007 San Francisco 13.4.2007, Symp. Y13.9

I. A. Denks, Ch. Genzel: "Enhancement of energy-dispersive residual stress analysis by considerationof detector electronic effects", in: Nucl. Instrum. Methods in Phys. Research B 262 (2007), 87 - 94

Ch. Genzel, I. A. Denks, J. Gibmeier, M. Klaus, G. Wagener: "The materials science synchrotron beamline EDD for energy-dispersive diffraction analysis", in: Nucl. Instrum. Methods in Phys. Research A 578 (2007), 23 - 33