Sub-Surface Residual Stress Gradients: Advances in Laboratory XRD Methods

2006 ◽  
Vol 524-525 ◽  
pp. 25-30 ◽  
Author(s):  
Cristy Leonor Azanza Ricardo ◽  
Mirco D'Incau ◽  
Paolo Scardi
Keyword(s):  
Residual Stress ◽  
Stress Gradient ◽  
Simple Algorithm ◽  
Typical Case ◽  
X Ray Diffraction ◽  
Metal Component ◽  
Surface Residual Stress ◽  
X Ray ◽  
X Ray Absorption ◽  
Residual Stress Gradient

A new algorithm is proposed to determine the through-thickness residual stress gradient by X-ray Diffraction measurements on progressively thinned components. The procedure is based on a chemical or electrochemical attack of the component surface, which is then measured at each thinning stage. The simple algorithm provided for by a specific norm has been revised to take into account the X-ray absorption effects and the conditions of mechanical equilibrium of the component. The new procedure is illustrated for a typical case of study concerning a shot-peened metal component.

Analysis of Residual Stress Gradients Below the Surface of a Material Using a Multi-Energy Method

2001 ◽  
Vol 678 ◽  
Author(s):  
Yanan Xiao ◽  
Tim Graber ◽  
Myungae Lee ◽  
Dale E. Wittmer ◽  
Susan M. Mini
Keyword(s):  
Residual Stress ◽  
Stress Gradient ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Gradient Distribution ◽  
X Ray ◽  
Experimental Parameters ◽  
The Relationship ◽  
X Ray Absorption ◽  
Residual Stress Gradient

AbstractThe residual-stress-gradient distribution just below the surface of a material is an important factor to consider during the engineering and design of a component. With the availability of an intense energy-tunable synchrotron x-ray source, it becomes easier to analyze the stress gradient below the surface, using a multi-energy x-ray diffraction method. A program was developed to efficiently determine possible experimental parameters using a sample with a known stress gradient distribution. In addition, this program can also calculate the stress gradient distribution below the surface taking into account experimental results. It also includes a subroutine for calculating the x-ray absorption coefficients of all of the elements, generalizing it for use with any material. As an example, in the present study, the relationship between x-ray energy and the residual stress gradient is discussed according to the calculated result for a silicon nitride composition.

scholarly journals Material Removal, Correction and Laboratory X-Ray Diffraction

2014 ◽  
Vol 996 ◽  
pp. 181-186 ◽  
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.

scholarly journals Influence of Surface Roughness on Evaluation of Stress Gradients in Coatings

2011 ◽  
Vol 681 ◽  
pp. 121-126 ◽  
Author(s):  
Andrey Benediktovich ◽  
Hugues Guerault ◽  
Ilya Feranchuk ◽  
V. Uglov ◽  
Alex Ulyanenkov
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Depth Profile ◽  
Stress Gradient ◽  
Grazing Incidence ◽  
Refraction Index ◽  
X Ray Diffraction ◽  
Wave Fields ◽  
X Ray ◽  
Residual Stress Gradient

Roughness influence on the residual stress gradient evaluation in the case of a grazing incidence X-ray diffraction setup is considered. In this geometry the surface roughness changes essentially the X-ray wave fields of the transmitted and diffracted beams inside the coatings and subsurface regions of bulk samples, and thus influences the refractive properties of the investigated sample area. In turn, the change in the refraction index enforces the re-scale of the informational depth and, consequently, the evaluated stress depth profile. The diffracted amplitude from the crystalline grain located beneath the surface is calculated. The surface roughness is shown to contribute into reconstruction of the real stress gradient profile of the coating.

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

2007 ◽  
Vol 40 (4) ◽  
pp. 675-683 ◽  
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.

Non-destructive Surface Residual Stress Profiling by Multireflection Grazing Incidence X-Ray Diffraction: a 7050 Al Alloy Study

2020 ◽  
Vol 60 (4) ◽  
pp. 475-480
Author(s):  
V. A. N. Righetti ◽  
T. M. B. Campos ◽  
L. B. Robatto ◽  
R. R. Rego ◽  
G. P. Thim
Keyword(s):  
Residual Stress ◽  
Grazing Incidence ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
X Ray ◽  
Non Destructive

Wear and Surface Residual Stress Evolution on Twin-Disc Tests of Rail/Wheel Steels

2013 ◽  
Vol 768-769 ◽  
pp. 707-713
Author(s):  
António Castanhola Batista ◽  
Daniel F.C. Peixoto ◽  
Joao P. Nobre ◽  
Luís Coelho ◽  
Diogo Mesquita Ramos ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Behavior ◽  
Contact Fatigue ◽  
Major Influence ◽  
Stress Evolution ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
Surface Residual Stress ◽  
X Ray ◽  
Initiation And Propagation

Twin disc tribological tests were performed in wheel and rail materials, with specimens taken from a Spanish AVE train wheel and a UIC60 rail, in a program intended to characterize their contact fatigue behavior. The X-ray diffraction technique was used to characterize the residual stress distribution at the initial and damaged stages, as well as in intermediate stages, since existing residual stresses in the surface layers of the railways steels and its evolution during contact loading can have a major influence on crack initiation and propagation.

scholarly journals Stress Gradient Analysis by Noncomplanar x-Ray Diffraction and Corresponding Refraction Correction

2014 ◽  
Vol 996 ◽  
pp. 162-168 ◽  
Author(s):  
Andrei Benediktovitch ◽  
Tatjana Ulyanenkova ◽  
Jozef Keckes ◽  
Alex Ulyanenkov
Keyword(s):  
Residual Stress ◽  
Gradient Analysis ◽  
Stress Gradient ◽  
X Ray Diffraction ◽  
Large Area ◽  
Present Contribution ◽  
Nondestructive Technique ◽  
X Ray ◽  
Tin Coatings ◽  
Measurement Geometry

X-ray residual stress analysis is a widespread nondestructive technique to investigate the residual stress and residual stress gradient in thin films and protective coatings.In the present contribution we introduce a new method based on the noncomplanar measurement geometry that allow to span large area of sin2ψ and penetration depth values without sample inclination. The refraction correction and absorption is considered in details for the noncomplanar measurements. The proposed technique is applied to determine stress gradients of blasted hard TiN coatings.

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

2006 ◽  
Vol 514-516 ◽  
pp. 1618-1622 ◽  
Author(s):  
Maria José Marques ◽  
J.C.P. Pina ◽  
A. Morão Dias
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Stress Gradient ◽  
Roughness Parameter ◽  
Diffraction Method ◽  
Grazing Incidence ◽  
Bragg Diffraction ◽  
X Ray Diffraction ◽  
Residual Surface Stress ◽  
X Ray

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.

Non-Destructive Residual Stress Analysis of Induction Hardened Components by Neutron and X-Ray Diffraction

2013 ◽  
Vol 768-769 ◽  
pp. 420-427 ◽  
Author(s):  
Jeremy Epp ◽  
Thilo Pirling ◽  
Thomas Hirsch
Keyword(s):  
Residual Stress ◽  
Chemical Composition ◽  
Residual Stresses ◽  
Stress Analysis ◽  
Stress Gradient ◽  
X Ray Diffraction ◽  
Neutron Measurement ◽  
X Ray ◽  
Layer Removal ◽  
Residual Stress Analysis

In this paper the microstructural and residual-stress analysis of an induction hardened plate of medium carbon steel is described. The stress gradient was determined using laboratory X-ray diffraction (IWT, Bremen, Germany) and neutron strain scanning (ILL, Grenoble, France). Due to slight variations of chemical composition in the depth, matchstick like (cross section 2×2mm²) d0-reference samples were prepared from a similarly treated sample. The d0shift induced by variation of chemical composition was measured by neutron and by X-ray diffraction along the strain free direction (sin²ψ*) and used for the evaluation of the neutron stress calculation. The d0distribution obtained from the neutron measurement did not appear reliable while the method using X-ray diffraction seems to be an efficient and reliable method to determine d0profiles in small samples. The evaluation of neutron measurements was then done using the X-ray diffraction d0distribution. High compressive residual stresses were measured in the hardened layer followed by high tensile residual stresses in the core. A comparison of the neutron measurements with X-ray diffraction (XRD) depth profiles obtained after successive layer removal showed that both methods give similar results. However, these investigations opened the question about the direct comparison of the residual stresses obtained by neutron and XRD. Indeed, a correction of the neutron data regarding the residual stresses in thickness direction might be necessary as these are released in the case of X-ray diffraction measurements after layer removal.

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