LABORATORY OF X-RAY DIFFRACTION (L-3) |
Scope of accreditation of research laboratory No AB 120
issued by Polish Centre for Accreditation Issue No. 17 of 12 June 2019.
Head of the laboratory | The experts |
Associate Prof. Anna Góral, Ph.D., D.Sc. | Anna Jarzębska, Ph.D., Eng Maciej Szczerba Ph.D., D.Sc. Zbigniew Światek, Ph.D., D.Sc. Anna Trelka-Druzic, MSc., Eng |
Address:
Institute of Metallurgy and Materials Science Polish Academy of Sciences
ul. Reymont 25, 30-059 Krakow
phone: (48) 12 295 28 98, fax: (48) 12 295 28 04
e-mail: Adres poczty elektronicznej jest chroniony przed robotami spamującymi. W przeglądarce musi być włączona obsługa JavaScript, żeby go zobaczyć. , website: http://www.imim.pl
Certified procedures:
1. X-Ray Phase Analysis (P/19/IB-08 edition 04 of 27.03.2013, mod.11.12.2013)
The procedure covers both qualitative (phase identification) and quantitative (volume fractions) phase analyses, the determination of crystal lattice parameters and estimation of the crystallite size in tested materials. An example of X-ray diffraction pattern is shown in Fig. 1. Remote control of measurement and data processing are realized by means of a computer system, which uses APD (Philips) or DIFFRACplus (Bruker AXS) programs and the ICDD crystallographic database.
Figure 1. X-ray diffraction pattern (2 THETA scan) for Mg-AZ31 alloy with deposited two-layer Al CrAlN coating registered at constant incident angle (15°). Filtered CoKα radiation was used. Positions of diffraction lines of the identified crystallographic phases are marked.
2. X-ray Diffraction Stress Analysis (P/19/IB-09 edition 03 of 14.07.2003, mod. 11.12.2013)
The procedure refers to the measurement of residual stresses by means of a non destructive X-ray diffraction method. The so called sin2ψ method is based on the displacement effect of diffraction lines in a stressed material with crystalline structure. The residual stress measurement is carried out on a flat surface of sample, the linear dimensions of which don't exceed value: 70 x 20 x 8 mm. The preparation of sample should be very careful in order not to disturb original state of stresses. Examined surface requires non-mechanical treatment, only chemical etching or electrochemical polishing is permissible.
Selection of the experiment parameters and identification of diffraction lines are realized by means of standardized programs (APD by Philips or DIFFRACplus by Bruker AXS and the ICDD crystallographic database) applied at home laboratory. Possible precision of the analysis depends on material and is determined individually in experimental way regarding a nominal position of the determined diffraction lines.
The experimental data of interplanar distances dhkl and X-ray elastic constants for examined materials are the input data for a computer program calculating the value of residual stresses. The program is owned by the L-3 laboratory. X-ray elastic constants are adjusted (matched) based on the subject literature, for example: monograph: G. Simmons, H. Wang Single Crystal Elastic Constant and Calculated Aggregate Properties. The M.I.T Press (1971) or another available literature.
An exemplar result of measurements expressed In interplanar lattice distance dhkl = f(sin2(ψ) are given in Fig. 2.
Figure 2. Graphical representation of dhkl = f(sin2(ψ) relation for the bear steel sample
The results of stress analysis are considered as credible, if the calculation error not exceeds 5%. Additionally, the 2-test of calculation procedure should take the value: 2 ≤ 2.3.
3. X-Ray Diffraction Texture Analysis (P/19/IB-0 edition 03 of 14.07.2003, mod. 11.12.2013)
It consists in recording diffraction effects and processing experimental data, which make possible to investigate the distribution of crystallographic orientation on the basis of the following characteristics illustrated in Figs. 3-6:
- incomplete pole figures registered by Schulz back-reflection method,
- orientation distribution function (ODF),
- complete pole figures, calculated from texture function,
- inverse pole figures.
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Figure 3. Incomplete (experimental) (left) and complete (calculated by means of the ODF) (right) (100)-pole figure of Ti (commercial purity) after severely deformed in equal-channel angular pressing (ECAP) process | Figure 4. Complete (111)-pole figure of cold rolled aluminum (commercial purity) registered with constant information depth 15 um, applied in the X-ray Texture Tomography |
Measurement and data acquisition control are carried out by our own devices, using the PHIL- TEX-, ScriptMaker- and VIS computer programmes. Experimental data are processed with one's own computer programmes (DAMFit, Generator, Interpolator) developed at the laboratory as well as by implemented one's own methods (ESA, ADC).
Figure 5. 3D (top) and 2D (bottom) view of selected section (2= 45°) of the Orientation Distribution Function for deep-drawing ferritic steel | Figure 6. Experimental- (top) and calculated- (middle) (111)-pole figure of cold-rolled (up to 65%) Copper, and related inverse pole figure of normal direction (ND) (bottom) |
4. Apparatus
The experimental tests resulting from the above-described investigation procedures are performed on D8-Discover (with a multicap beam optics and linear detector LynxEye), PW 1710, PW 1830 X'Pert System (equipped with ATC-3 texture goniometer) (see Fig. 7) and D2 Phaser (with an energy-dispersive detector XFlash) (see Fig. 8). In the standard procedures, filtered K-series of Co target radiation is used. If necessary, Cu or Cr targets can be applied as well. Diffracted beam monochromatization applied in the phase analysis is accomplished by means of a graphite monochromator. Texture analysis uses beam formation system, which enables changing its geometrical parameters, depending on the tested material. Nominally, the apparatus is equipped with two independent arrangements of proportional detectors.
5. Preparation of samples for testing
Geometrical dimensions of samples for the above-mentioned X-ray testing should allow a sample to be fitted in a cylinder 32 mm in diameter and 8 mm of height. The sample surface to be tested has to be smooth and clean. Depending on the kind of material and type of analysis, the mechanical surface treatment (grinding, cutting) and polishing on discs and abrasive papers with final gradation smaller than 600 should be applied to the sample. In justified cases, the surface should be additionally polished mechanically or electrochemically.
Persons interested in co-operation should contact:
The Head of the Laboratory L-3:
Anna Góral Ph.D.,Eng
phone: +48 12 295 28 68, e-mail: Adres poczty elektronicznej jest chroniony przed robotami spamującymi. W przeglądarce musi być włączona obsługa JavaScript, żeby go zobaczyć.
