Evaluation of extremely steep residual stress gradients based on a combined approach using laboratory-scale equipment

Surface treatments characterized by rapid heating and cooling (e.g. laser hardening) can induce very steep residual stress gradients in the direct vicinity of the area being treated. These gradients cannot be characterized with sufficient accuracy by means of the classical sin2Ψ approach applying angle-dispersive X-ray diffraction. This can be mainly attributed to limitations of the material removal method. In order to resolve residual stress gradients in these regions without affecting the residual stress equilibrium, another angle-dispersive approach, i.e. the universal plot method, can be used. A novel combination of the two approaches (sin2Ψ and universal plot) is introduced in the present work. Prevailing limits with respect to profiles as a function of depth can be overcome and, thus, high-resolution surface layer characterization is enabled. The data obtained are discussed comprehensively in comparison with results elaborated by energy-dispersive X-ray diffraction measurements.

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Revision and extension of the standard laboratory technique for X-ray diffraction measurement of residual stress gradients

Journal of Applied Crystallography ◽

10.1107/s0021889807022935 ◽

2007 ◽

Vol 40 (4) ◽

pp. 675-683 ◽

Cited By ~ 12

Author(s):

Cristy L. Azanza Ricardo ◽

Mirco D'Incau ◽

Paolo Scardi

Keyword(s):

Residual Stress ◽

Hole Drilling ◽

Al Alloy ◽

Diffraction Measurement ◽

X Ray Diffraction ◽

Surface Residual Stress ◽

X Ray ◽

Stress Gradients ◽

Layer Removal ◽

Removal Technique

A new procedure is proposed to determine sub-surface residual stress gradients by laboratory X-ray diffraction measurements at different depths using a chemical layer-removal technique. The standard correction algorithm for stress relaxation due to layer removal is improved by including corrections for X-ray absorption, and by the addition of constraints imposed by the mechanical equilibrium conditions. Besides correcting the data,i.e.providing more reliable through-thickness residual stress trends, the proposed procedure also provides an elastically compatible and plausible estimate of the residual stress inside the component, well beyond the measured region. The application of the model is illustrated for a set of Al-alloy components shot-peened at different Almen intensities. Results are compared with those given by `blind hole drilling', which is an independent and partly destructive method.

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Analysis of Residual Stress Gradients in Thin Films Using SEEMANN-BOHLIN-X-Ray Diffraction

Materials Science Forum ◽

10.4028/www.scientific.net/msf.228-231.301 ◽

1996 ◽

Vol 228-231 ◽

pp. 301-306 ◽

Cited By ~ 5

Author(s):

K. Fischer ◽

H. Oettel

Keyword(s):

Thin Films ◽

Residual Stress ◽

X Ray Diffraction ◽

X Ray ◽

Stress Gradients

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Material Removal, Correction and Laboratory X-Ray Diffraction

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.996.181 ◽

2014 ◽

Vol 996 ◽

pp. 181-186 ◽

Cited By ~ 1

Author(s):

Eric Wasniewski ◽

Baptiste Honnart ◽

Fabien Lefebvre ◽

Eric Usmial

Keyword(s):

Residual Stress ◽

Stress Relaxation ◽

Stress Field ◽

Residual Stresses ◽

Material Removal ◽

Stress Gradient ◽

X Ray Diffraction ◽

X Ray ◽

Surface Residual Stresses ◽

Residual Stress Gradient

Laboratory X-ray diffraction is commonly used for surface residual stresses determination. Nevertheless, the in-depth residual stress gradient also needs to be known. Chemical or electro-polishing method is generally used for material removal. However, material removal may seek a new equilibrium and stress field may change in such a way that experimental residual stress values must be corrected. Different methods exist to account for the residual stress relaxation associated with the material removal operation and will be discussed in this paper.

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S48 X-ray Diffraction at Constant Penetration Depth — A Viable Approach for Characterizing Steep Residual Stress Gradients

Powder Diffraction ◽

10.1154/1.2951808 ◽

2008 ◽

Vol 23 (2) ◽

pp. 187-187 ◽

Cited By ~ 1

Author(s):

T. Erbacher ◽

A. Wanner ◽

O. Vöhringer ◽

T. Beck

Keyword(s):

Residual Stress ◽

Penetration Depth ◽

X Ray Diffraction ◽

X Ray ◽

Stress Gradients ◽

Viable Approach

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Control of Residual Stresses in As-Grown Polysilicon by Multi-Layer Deposition: The “Multipoly” Process

MRS Proceedings ◽

10.1557/proc-605-37 ◽

1999 ◽

Vol 605 ◽

Author(s):

Hie Yang ◽

H. Kahn ◽

A.Q. He ◽

S.M. Phillips ◽

A.H. Heuer

Keyword(s):

Residual Stress ◽

X Ray Diffraction ◽

Columnar Microstructure ◽

X Ray ◽

Stress Gradients ◽

Compressive Stresses ◽

Transmission Electron ◽

Layer Deposition ◽

Polysilicon Films ◽

The Individual

AbstractLPCVD polysilicon thin films deposited between ∼550 and ∼600 °C have an equiaxed microstructure (resulting from crystallization of an initially amorphous deposit) and contain ∼200 MPa residual tensile stresses after deposition, whereas polysilicon films deposited above ∼600 °C have a columnar microstructure and contain ∼300 MPa residual compressive stresses after deposition. Both types of films also contain stress gradients.We have grown films containing multiple layers of polysilicon ("MultiPoly") by cycling the growth temperature between 570 and 615 °C. The multilayer films thus formed are comprised of alternating tensile and compressive layers, and by control of the thickness of the individual layers, the overall stress of the polysilicon can display any value between that of the tensile layer and that of the compressive layer. We have focussed on producing films with zero overall residual stress, as measured by wafer curvature, and have characterized the microstructures by transmission electron microscopy (TEM) and X-ray diffraction (XRD).Because of the stress gradients present in both layers, devices made from films with zero overall residual stress may show distortions after release. We have measured the stress gradients in each type of layer and can design films with zero overall stress and zero overall stress gradients. It is also possible to design films with any level of overall (tensile or compressive) stress but with controlled displacements upon release.

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Mapping Residual Stress Gradients in Automotive Components Via X-Ray Diffraction

10.4271/2007-01-0802 ◽

2007 ◽

Cited By ~ 1

Author(s):

J. Pineault ◽

M. Belassel ◽

M. Brauss ◽

J. Ladouceur

Keyword(s):

Residual Stress ◽

X Ray Diffraction ◽

X Ray ◽

Stress Gradients ◽

Automotive Components

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Intermethod Comparison and Evaluation of Measured Near Surface Residual Stress in Milled Aluminum

Experimental Mechanics ◽

10.1007/s11340-021-00734-5 ◽

2021 ◽

Author(s):

C. R. Chighizola ◽

C. R. D’Elia ◽

D. Weber ◽

B. Kirsch ◽

J. C. Aurich ◽

...

Keyword(s):

Residual Stress ◽

Material Removal ◽

Flat Surface ◽

Cutting Speed ◽

Hole Drilling ◽

X Ray Diffraction ◽

Surface Residual Stress ◽

Near Surface ◽

X Ray ◽

Milled Surface

Abstract Background While near surface residual stress (NSRS) from milling is a driver for distortion in aluminum parts there are few studies that directly compare available techniques for NSRS measurement. Objective We report application and assessment of four different techniques for evaluating residual stress versus depth in milled aluminum parts. Methods The four techniques are: hole-drilling, slotting, cos(α) x-ray diffraction (XRD), and sin2(ψ) XRD, all including incremental material removal to produce a stress versus depth profile. The milled aluminum parts are cut from stress-relieved plate, AA7050-T7451, with a range of table and tool speeds used to mill a large flat surface in several samples. NSRS measurements are made at specified locations on each sample. Results Resulting data show that NSRS from three techniques are in general agreement: hole-drilling, slotting, and sin2(ψ) XRD. At shallow depths (< 0.03 mm), sin2(ψ) XRD data have the best repeatability (< 15 MPa), but at larger depths (> 0.04 mm) hole-drilling and slotting have the best repeatability (< 10 MPa). NSRS data from cos(α) XRD differ from data provided by other techniques and the data are less repeatable. NSRS data for different milling parameters show that the depth of NSRS increases with feed per tooth and is unaffected by cutting speed. Conclusion Hole-drilling, slotting, and sin2(ψ) XRD provided comparable results when assessing milling-induced near surface residual stress in aluminum. Combining a simple distortion test, comprising removal of a 1 mm thick wafer at the milled surface, with a companion stress analysis showed that NSRS data from hole-drilling are most consistent with milling-induced distortion.

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