A Practical ϕ-Method for the Evaluation of Stress on Materials with Stress Gradient by X-rays

1984 ◽  
Vol 28 ◽  
pp. 265-274 ◽  
Author(s):  
Toshihiko Sasaki ◽  
Makoto Kuramoto ◽  
Yasuo Yoshioka
Keyword(s):  
Stress Measurement ◽  
Stress Gradient ◽  
X Rays ◽  
Present Stage ◽  
Linear Distribution ◽  
Triaxial Stress State ◽  
X Ray ◽  
Depth Direction ◽  
Textured Materials ◽  
Distribution Of Stress

Nonlinear sin2ψ curves are often obtained in X-ray stress measurement. One of the reasons, for non-textured materials, is a steep stress gradient snowing in a surface layer of a sample. Regarding such experimental results, several new principles have been developed for X-ray stress analysis. At the present stage, we can evaluate the stress gradient in a triaxial stress state. As the next stage of the investigation, it is necessary to consider the validity of the assumptions taken in the principle, especially, the assumption about linear distribution of stress along the depth direction.

Application of Image Plate to X-Ray Stress Measurement of Surface Thin Layer

2010 ◽  
Vol 89-91 ◽  
pp. 383-388
Author(s):  
Toshihiko Sasaki ◽  
Yohei Miyazawa ◽  
Masanari Yoshida ◽  
Kazuto Fukuda
Keyword(s):  
Evaluation Method ◽  
Stress Measurement ◽  
Incidence Angle ◽  
Stress Gradient ◽  
Real Space ◽  
X Rays ◽  
X Ray ◽  
Area Detector ◽  
Residual Stress State ◽  
Debye Ring

In this study, the authors made an experiment to observe the residual stress state in the surface of the engineered parts (for example, shot-peened steel) by X-ray stress measurement. An evaluation method was proposed for the stress gradient from the information on the X-ray Debye ring obtained with an area detector. The method utilized the fact that the X-ray penetration depth is a function of the central angle of the Debye ring α. It varies due to a section of Debye ring. It also depends on the incidence angle of X-rays and the wavelength used. Mean stress over the whole penetration depths of X-rays, which is defined as the Laplace stress, was measured by the cosα method[1, 2] by using this characteristic, and the real space stress[3-5] gradient was evaluated.

X-Ray stress measurement on steels having preferred-orientation

1977 ◽  
Vol 12 (1) ◽  
pp. 62-65 ◽  
Author(s):  
H Dölle ◽  
V Hauk ◽  
H Kockelmann ◽  
H Sesemann
Keyword(s):  
Interplanar Spacing ◽  
Stress Measurement ◽  
Preferred Orientation ◽  
Linear Distribution ◽  
Stress Evaluation ◽  
X Ray ◽  
Non Linear ◽  
Formed Structure

A non-linear distribution of (211) interplanar spacing is shown to occur in textured steels, the reasons for the non-linearity being marked texture, cold-formed structure and stresses. For stress evaluation it is recommended that the directions ψ be used, which are independent of texture. The paper gives the modified sin2ψ method, for both film and goniometer techniques, for predominantly uniaxial stresses.

scholarly journals Influence of Layer Removal Methods in Residual Stress Profiling of a Shot Peened Steel Using X-Ray Diffraction

2014 ◽  
Vol 996 ◽  
pp. 175-180 ◽  
Author(s):  
Rasha Alkaisee ◽  
Ru Lin Peng
Keyword(s):  
Residual Stress ◽  
Chemical Etching ◽  
Stress Measurement ◽  
Diffraction Measurement ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Layer Removal ◽  
Compressive Stresses ◽  
The Difference

For X-Ray Diffraction Measurement of Depth Profiles of Residual Stress, Step-Wise Removal of Materials has to be Done to Expose the Underneath Layers to the X-Rays. this Paper Investigates the Influence of Layer Removal Methods, Including Electro-Polishing in Two Different Electrolytes and Chemical Etching, on the Accuracy of Residual Stress Measurement. Measurements on Two Shot-Peened Steels Revealed Large Discrepancy in Subsurface Distributions of Residual Stress Obtained with the Respective Methods. Especially, the Chemical Etching Yielded much Lower Subsurface Compressive Stresses than the Electro-Polishing Using a so Called AII Electrolyte. the Difference was Explained by the Influence of the Different Layer Removal Methods on the Microscopic Roughness.

Thermal and Electromigration Strain Distributions in 10 μm-Wide Aluminum Conductor Lines Measured by X-Ray Microdiffraction

1997 ◽  
Vol 473 ◽  
Author(s):  
P.-C. Wang ◽  
G. S. Cargill ◽  
I. C. Noyan ◽  
E. G. Liniger ◽  
C.-K. Hu ◽  
...  
Keyword(s):  
Thermal Stresses ◽  
Stress Gradient ◽  
Thermal Strain ◽  
Sample Surface ◽  
X Rays ◽  
Strain Measurements ◽  
X Ray ◽  
Glass Capillaries ◽  
Reflection Geometry ◽  
Made In

ABSTRACTX-ray microdiffraction was applied to study the thermal and electromigration strains in 10 μm-wide Al conductor lines with 10 μm spatial resolution. X-rays were collimated either by pinholes or by tapered glass capillaries to form x-ray microbeams. Measurements were made in a symmetric-reflection geometry so that the strains normal to the sample surface could be examined at different positions along the conductor lines. Results of thermal strain measurements show that the SiO2 passivation plays an important role in limiting relaxation of in-plane compressive thermal stresses in the Al lines, but that the passivation is not effective in confining the overall thermal expansion of the Al line along the film normal. Electromigration strain measurements show that a linear stress gradient developed within the first hour of electromigration. The magnitude of the stress gradient changed little until fast stress relaxations occurred near the anode end of the line. Possible mechanisms are discussed in light of these observations.

X-ray Multiaxial Stress Analysis on Materials with Stress Gradient by Use of Cos Ψ Function

1984 ◽  
Vol 28 ◽  
pp. 255-264 ◽  
Author(s):  
Yasuo Yoshioka ◽  
Toshihiko Sasaki ◽  
Makoto Kuramoto
Keyword(s):  
Residual Stresses ◽  
Stress Analysis ◽  
Stress Tensor ◽  
Penetration Depth ◽  
Stress Gradient ◽  
X Rays ◽  
Average Strain ◽  
X Ray ◽  
Stress Gradients ◽  
Stress Components

When X-ray residual stresses are determined taking into account the stress gradients within the penetration depth of X-rays, three assumptions have usually been made; 1) the stress gradient is linear in respect to the depth from the specimen surface, 2) the penetration depth of X-rays is a function of Sin2ψ and 3) the strain measured by X-rays corresponds to the average strain weighted on the intensity of the diffracted X-rays. However, the assumption of the penetration depth of X-rays is the reason we sometimes observed noticeable errors which depend on the combination of stress components in the stress tensor.

Estimation of Ahisotropy of X-Ray Elastic Modulus in Steel Sheets

1985 ◽  
Vol 29 ◽  
pp. 21-28 ◽  
Author(s):  
Shin-ichi Nagashima ◽  
Masaki Shiratori ◽  
Ryuichi Nakagawa
Keyword(s):  
Elastic Modulus ◽  
Stress Measurement ◽  
Three Dimensional ◽  
Orientation Distribution ◽  
Vector Method ◽  
X Ray ◽  
Steel Sheets ◽  
Lattice Strains ◽  
Stress Ratios ◽  
Textured Materials

The oscillation from a linear relation in the 20 vs. sin2ψ diagram has been a most important problem in X-ray stress measurement. There are, therefore, a number of papers concerned with the X-ray elastic constant, lattice strains under stresses and evaluation of stresses of textured materials.The purpose of the present study is to analyze the three-dimensional orientation distribution of steel sheets by means of the Vector method proposed by Ruer and Baro, and to calculate the elastic modulus of textured sheets by means of a finite element method (FEM) using the three-dimensional orientation distribution, and then to calculate the strain/stress ratios vs. the directions defined by the angles between the specimen normal and the normal to the diffracting planes.

X-Ray Stress Measurement of Ni-Ai System Intermetallic Compounds

1995 ◽  
Vol 39 ◽  
pp. 243-249
Author(s):  
Tokimasa Goto ◽  
Hiroyuki Tabata ◽  
Yukio Hirose
Keyword(s):  
Intermetallic Compounds ◽  
Stress Measurement ◽  
Preferred Orientation ◽  
Coarse Grain ◽  
X Rays ◽  
Melting Method ◽  
X Ray ◽  
Arc Melting ◽  
Coarse Grains ◽  
Heat Resisting Materials

The microstructures and mechanical properties of Ni-Al system intermetallic compounds used as heat resisting materials have been investigated by many researchers[l,2], but there are few studies applying X-ray stress measurement to these materials[3]. Two problems make it difficult: One is the comparatively coarse grain size, the other is the strong preferred orientation along the direction of the solidification. Therefore, it become possible to evaluate mechanical behavior in these materials, if we can measure the residual stresses correctlv by X-rays.In this paper, Ni-25mol%AI(Ni3Al) made by the arc-melting method was employed. It consists of comparatively coarse grains and has strong preferred orientation along the direction of the solidification.

Spalling Stress in Oxidized Thermal Barrier Coatings Evaluated by X-Ray Diffraction Method

2005 ◽  
Vol 490-491 ◽  
pp. 631-636 ◽  
Author(s):  
Kenji Suzuki ◽  
Keisuke Tanaka
Keyword(s):  
Thermal Barrier Coatings ◽  
Plane Stress ◽  
Stress Measurement ◽  
Diffraction Method ◽  
High Energy ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
X Rays ◽  
Barrier Coatings ◽  
X Ray

The spallation of thermal barrier coatings (TBCs) is promoted by thermally grown oxide (TGO). To improve TBCs, it is very important to understand the influence of TGO on the spalling stress. In this study ,the TBCs were oxidized at 1373 K for four diferent periods: 0, 500,1000 and 2000 h. The distribution of the in-plane stress in oxidized TBCs, s1, was obtained by repeating the X-ray stress measurement with low energy X-rays after successive removal of the surface layer. The distribution of the out-of-plane stress, s1− s3, was measured with hard synchrotron X-rays, because high energry X-rays have a large penetration depth. From the results by the low and high energy Xrays, the spalling stress in the oxidized TBCs, s3, was evaluated. The evaluated value of the spalling stress for the oxidized TBC was a small tension beneath the surface, but steeply increased near the interface between the top and bond coating. This large tensile stress near the interface is responsible for the spalling of the top coating.

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