Determination of Strain and Stress Fields by Diffraction Methods

Noyan, I. C.; Cohen, J. B.

doi:10.1007/978-1-4613-9570-6_5

Cited by 258 publications

(311 citation statements)

References 20 publications

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“…8) with maximum orientation density of 5.66 multiples of random distribution. DECs may also exhibit variations by plastically deforming the material prior to the tensile testing [20].…”

Section: Diffraction Elastic Constantsmentioning

confidence: 99%

Determination of polycrystal diffraction elastic constants of Ti–2.5Cu by using in situ tensile loading and synchrotron radiation

Maawad

Brokmeier

Zhong

et al. 2014

Materials Science and Engineering: A

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Residual stress determination in engineering components from diffraction strain measurements needs reliable diffraction elastic constants (DECs). From this sense, in situ uniaxial tensile loading experiment was performed on alpha titanium alloy Ti-2.5Cu at the HEMS beamline at DESY by means of a monochromatic synchrotron X-ray diffraction. A comparison between measured (polycrystal) and calculated (single crystal) DECs using for example Kröner model was presented and discussed. The results revealed that the measured DECs slightly differ from the calculated ones. Furthermore, changes in the lattice parameters a and c as well as c/a ratio during tensile loading were also investigated.

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“…8) with maximum orientation density of 5.66 multiples of random distribution. DECs may also exhibit variations by plastically deforming the material prior to the tensile testing [20].…”

Section: Diffraction Elastic Constantsmentioning

confidence: 99%

Determination of polycrystal diffraction elastic constants of Ti–2.5Cu by using in situ tensile loading and synchrotron radiation

Maawad

Brokmeier

Zhong

et al. 2014

Materials Science and Engineering: A

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“…The steels selected range from low-tomedium strength. The corresponding relaxation behaviors of the residual stresses present in welded samples subjected to cyclic loading were measured by X-ray diffraction method, [34][35][36][37][38] and the results obtained are presented later. These results are related to the observed microstructures and are discussed in light of possible dislocation movement in the materials.…”

Section: Introductionmentioning

confidence: 99%

The Residual Stress Relaxation Behavior of Weldments During Cyclic Loading

Qian

Chumbley

Karakulak

et al. 2013

Metall Mater Trans A

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Accurate measurement of residual stress is necessary to obtain reliable predictions of fatigue lifetime and enable estimation of time-to-facture for any given stress level. In this article, relaxation of welding residual stresses as a function of cyclic loading was documented on three common steels: AISI 1008, ASTM A572, and AISI 4142. Welded specimens were subjected to cyclic bending (R = 0.1) at different applied stresses, and the residual stress relaxation existing near the welds was measured as a function of cycles. The steels exhibited very different stress relaxation behaviors during cyclic loadings, which can be related to the differences in the microstructures of the specimens. A phenomenological model, which treats dislocation motion during cyclic loading as being analogous to creep of dislocations, is proposed for estimation of the residual stress relaxation. Accurate measurement of residual stress is necessary to obtain reliable predictions of fatigue lifetime and enable estimation of time-to-facture for any given stress level. In this article, relaxation of welding residual stresses as a function of cyclic loading was documented on three common steels: AISI 1008, ASTM A572, and AISI 4142. Welded specimens were subjected to cyclic bending (R = 0.1) at different applied stresses, and the residual stress relaxation existing near the welds was measured as a function of cycles. The steels exhibited very different stress relaxation behaviors during cyclic loadings, which can be related to the differences in the microstructures of the specimens. A phenomenological model, which treats dislocation motion during cyclic loading as being analogous to creep of dislocations, is proposed for estimation of the residual stress relaxation. Keywords Surfaces and Interfaces, Thin Films Nanotechnology

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“…In order to study the in -depth average strain profile, three different X-rays penetration depths were employed by controlling the beam angle of incidence. The effective penetration depth for each x-ray incidence angle was calculated according to Noyan [13], assuming a layer of material contributing with 63% to the total diffracted intensity. The incidence angles and the corresponding calculated penetration depths for a 7.0 keV x-ray beam are shown in Table 1.…”

Section: Set I: Sample Preparationmentioning

confidence: 99%

Effect of bombarding steel with Xe+ ions on the surface nanostructure and on pulsed plasma nitriding process

Cucatti

Ochoa

Morales

et al. 2015

Materials Chemistry and Physics

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The modification of steel (AISI 316L and AISI 4140) surface morphology and underlying inter-crystalline grains strain due to Xe + ion bombardment are reported to affect nitrogen diffusion after a pulsed plasma nitriding process. The ion bombardment induces regular nanometric patterns and increases the roughness of the material surface. The strain induced by the noble gas bombardment is observed in depths which are orders of magnitude larger than the projectiles' stopping distance. The pre-bombarded samples show peculiar microstructures formed in the nitrided layers, modifying the in-depth hardness profile. Unlike the double nitrided layer normally obtained in austenitic stainless steel by pulsed plasma nitriding process, the Xe + pre-bombardment treatment leads to a single thick compact layer. In nitrided pre-bombarded AISI 4140 steel, the diffusion zone shows long iron nitride needleshaped precipitates, while in non-pre-bombarded samples finer precipitates are distributed in the material. Keywords: Surface modification, ion-beam bombardment, plasma nitriding, microstrain S. Cucatti et al., Materials Chemistry and Physics, Volumes 149-150, (2015), pp. 261-269 DOI http://dx.doi.org/10.1016/j.matchemphys.2014.10.015 DOI: http://dx.doi.org/10.1016/j.matchemphys.2014.10.015 2 IntroductionSurface texturing is an important method applied in various technological areas of research. Much of the current interest in surface modifications stems from the possibility of obtaining special optical, tribological, and mechanical properties in a variety of materials [1,2]. In particular, texturing steels surface by ionic bombardment (atomic attrition) is an interesting route to modify plasma nitriding processes. The efficiency of the process and the final material properties are influenced by modifications of the surface and bulk material such as roughness, defects, and stress created by ion impact. Moreover, a combination of low energy argon ion bombardment and substrate temperature modified diffusion phenomena in semiconductors [3]. Other surface modifications such as mechanical attrition ("shot-penning") generate stress, plastic deformation, defects and roughness. All these changes contribute to modify the kinetic of the surface reactions, shortening the duration of nitriding processes [4,5,6]. Results reported by Abrasonis et al. suggest that the effect of bombarding the material with Ar + ions after nitriding processes also has important consequences on nitrogen diffusion in austenitic stainless steel [7]. The observed changes in plasma nitriding processes are attributed to several concomitant causes such as increasing the surface roughness, stress, and creation of lattice defects, altogether improving nitrogen diffusion [8,9]. Moreover, in the nitriding process, precipitation kinetics lead to possibly complex stress profiles even considering smoothly decreasing nitrogen profiles influencing nitrogen diffusion [10].In this work we expand the study reported by Ochoa et al. [8,9] by considering the state of the bombard...

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Determination of Strain and Stress Fields by Diffraction Methods

Abstract: the strains in the sample coordinate system can be expressed in terms of stresses by the inverse of Eq. (5.9):(5.12 )

Cited by 258 publications

References 20 publications

Determination of polycrystal diffraction elastic constants of Ti–2.5Cu by using in situ tensile loading and synchrotron radiation

Determination of polycrystal diffraction elastic constants of Ti–2.5Cu by using in situ tensile loading and synchrotron radiation

The Residual Stress Relaxation Behavior of Weldments During Cyclic Loading

Effect of bombarding steel with Xe+ ions on the surface nanostructure and on pulsed plasma nitriding process

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