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The Residual Stress Measurement Program at the NCNR

 The Residual Stress Measurement Program at the NCNR

Diffraction stress analysis at the NCNR is done for the most part using the neutron diffractometer BT8 but also includes a new X-ray diffractometer and regular measurements at the Advanced Photon Source in Argonne, IL. Together, the three methods cover the entire range of depths from which strain information can be retrieved by diffraction. Examples of recent projects include both extremes - first a 0.05 mm x 0.5 mm, tighly collimated, 20 keV synchrotron X-ray beam used for a 1.2 10-3 mm3 sampling volume, and a 5 mm by 5 mm neutron beam used for a 125 mm3 sampling volume. Besides strain, elastic constants are also measured. Bulk elastic constants are measured through four-point bending. Uniaxial tension is also possible, provided that the specimen length is sufficient. Diffraction elastic constants are measured using neutrons either in uniaxial tension or compression. With the addition of a new X-ray diffractometer it is also possible to measure DEC with a four-point bending device.

Group members :

Team Leader :    Henry J. Prask (301-975-6226,

Responsible scientist for Neutron and X-ray Diffractometers, Synchrotron Strain Measurements:
   Thomas Gnaeupel-Herold (301-975-5380,

Postdoc (Texture Analysis, Software Development):    Vladimir Luzin (301-975-5303,

Recent Publications:

T.Gnäupel-Herold, H. Prask, J. Fisher and X. Cheng, Residual Stress Modification by Means of Ultrasonic Impact Treatment, Proceedings of the SEM Annual Conference on Experimental and Applied Mechanics, June, 2001, Portland, Oregon, pp. 551-554.

M. Popovici, A. D. Stoica, C. R. Hubbard, S. Spooner, H. J. Prask, T. H. Gnaeupel-Herold, P. M. Gehring and R. W. Erwin, Multi-wafer focusing neutron monochromators and applications, in: Neutron Optics, James L. Wood and Ian S. Anderson, Editors, Proceedings of SPIE, Volume 4509, pp. 21-32 (2001).

T.Gnäupel-Herold, H.J. Prask, F.S. Biancaniello, Residual Stresses and Elastic Constants in Thermal Deposits, in: E.E. Gdoutos (ed.), Recent Advances in Experimental Mechanics - In Honor of Isaac M. Daniel, Kluwer Academic Publishers, Dordrecht 2002

V. Luzin, T.Gnäupel-Herold, H.J. Prask, Evaluation of Local and Global Elastic Properties of Textured Polycrystals by Means of FEM, Materials Science Forum 408-412 (2002), pp 407-412

W. M. Gibson, A.J. Schultz, H.H. Chen-Mayer, D.F.R. Mildner, T.Gnäupel-Herold, M.E. Miller, H.J. Prask, R. Vitt, R. Youngman, J.M. Carpenter, Polycapillary focusing optic for small-sample neutron crystallography, J. Applied Cryst. 35, 677-683 (2002)

P. Reynolds, Wei Tang, T. Gnaupel-Herold, and H. Prask, Structure, Properties, and Residual Stress of 304L Stainless Steel Friction Stir Welds, accepted for publication in Scripta Met. (2003)

BT8 Home page
Ancillary Equipment

Last modified 03-April-2003 by website owner: NCNR (attn: Thomas Gnaeupel-Herold)