Influence of Surface Roughness on the Quality of Data Obtained by Pseudo-Grazing Incidence X-Ray Diffraction


Article Preview

The conventional Bragg diffraction geometry, normally used to characterize the residual surface stress state, it is not suitable to evaluate surface treated materials and thin films. The X-ray path lengths through a surface layer or thin film are too short to produce adequate diffraction intensities in relation to the bulk or the substrate. Another limitation of the conventional technique appears when a residual stress gradient is present in the irradiated surface. The technique only enables the evaluation of the mean value of this gradient. In these cases, a recently proposed Pseudo-Grazing Incident X-ray Diffraction method would be better applicable. In this study, the Pseudo-Grazing Incidence X-ray Diffraction is applied to characterize the residual stress depth profiles of several AISI 4140 samples, which were prepared, by mechanical polishing and grinding, in order to present different surface roughness parameters, Ra. The experimental results lead to the conclusion that the surface roughness limits the application of the Pseudo-Grazing Incidence methodology to a minimum X-ray incident angle. This angle is the one that enables a mean X-ray penetration depth with the same order of magnitude of the sample surface roughness parameter, Ra.



Materials Science Forum (Volumes 514-516)

Edited by:

Paula Maria Vilarinho




M. J. Marques et al., "Influence of Surface Roughness on the Quality of Data Obtained by Pseudo-Grazing Incidence X-Ray Diffraction", Materials Science Forum, Vols. 514-516, pp. 1618-1622, 2006

Online since:

May 2006




[1] C.I. Noyan, J.B. Cohen: Residual stress, measurement by diffraction and interpretation, Springer-Verlag, New York, (1987).

[2] M. François, J.M. Sprauel, C.F. Déhan et al: X-ray diffraction method, Handbook of measurement of residual stresses, Society for Experimental Mechanics, Inc., Ed. J. Lu, The Fairmont Press, Lilburn, (1996), pp.71-131.

[3] V. Hauk: Structural and residual stress analysis by nondestructive methods. Evaluation - Application - Assessment., 1 st edition, Elsevier Science B. V., Amsterdam, (1997).

[4] M.J. Marques, A.M. Dias, P. Gergaud, J.L. Lebrun: A methodology development for the study of near surface stress gradients, Materials Science & Engineering, A287 (2000), pp.78-86.


[5] A. Schubert, B. Kämpfe, E. Auerswald, B. Michel: X-ray analysis of residual stress gradients and textures in thin coatings, Residual Stresses, Ed. V. Hauk, H.P. Hougardy, E. Macherauch e H. -D. Tietz, DGM Informationsgesellschaft mbH, Verlag, Oberusel, (1992).


[6] T. Dümmer, B. Eigenmann, D. Löhe: Recent advances in the depth-resolved X-ray analysis of residual stresses and stress-free lattice parameters in Ti(C-N) gradient coatings, Proc. Third International Conference on Computer Methods and Experimental Measurements for Surface Treatment Effects; Surface Treatment, Oxford, UK, July 15-17 1997, Ed. M.H. Aliabadi e C.A. Brebbia, Computational Mechanics Publications, Southampton, Boston, 1997, pp.371-379.


[7] C. Houpert, H. Michaud, O. Valfort: The use of soller sllts to evaluate stress gradients by Xray diffraction, Proc. The Fourth International Conference on Residual Stresses (ICRS4), Baltimore, Maryland, USA, 8-10 June 1994, Society for Experimental Mechanics, Bethel, USA vol. 1 (1994).

[8] W.F. Hosford: The Oxford Engineering Science Series, The Mechanics of Crystals and Textured Polycrystals, Ed. A.L. Cullen e L.C. Woods, The Oxford Engineering Science Series, 32, Oxford University Press, New York, (1993), p.16.