Investigation of complex residual stress states in the near-surface region: Evaluation of the complete stress tensor by X-ray diffraction pattern decomposition

2019 ◽  
Vol 466 ◽  
pp. 151-164 ◽  
Author(s):  
Peter Schoderböck
2012 ◽  
Vol 729 ◽  
pp. 199-204 ◽  
Author(s):  
Dávid Cseh ◽  
Valéria Mertinger

Residual stresses have a fundamental effect on the operational behaviour and lifetime of industrial products. The fatigue resistance of machine parts can be increased by introducing residual compressive stresses into the surface region. For certain machine parts especially in the vehicle industry the residual stress is strongly demanded by the quality control. For this reason, measuring the stress accurately is becoming increasingly important. The Almen test, which only gives a qualitative result, is widely used in the industry. Shot peening and rolling are methods which are suitable for creating elastic residual stresses. This paper examines the technologies used by Rába Futómű Nyrt. to increase the lifetime by means of residual stress. We performed analysis of the residual stress of samples shot peened the same way but under different heat treatment states. We compared the residual stress values of burnished and hardened shaft joints, and the residual stress states of gear made of hardened alloy, comparing the carbonized ones to ones which were shot peened under small intensity.


1999 ◽  
Vol 32 (4) ◽  
pp. 779-787 ◽  
Author(s):  
Ch. Genzel ◽  
M. Broda ◽  
D. Dantz ◽  
W. Reimers

The application of the formalism for residual-stress gradient evaluation based on the measuring principle of the scattering-vector method, which has been derived in the first paper of this series [Genzel (1999).J. Appl. Cryst.32, 770–778], is demonstrated by practical examples. Depending on the statistical scattering of the experimental data, either biaxial or even triaxial residual-stress states may be analysed; the latter case yields self-consistently the depth profiles of the in-plane stresses, σ11(τ) and σ22(τ), the normal stress component, σ33(τ), as well as the strain-free lattice spacing,d0(hkl). The results obtained by this new evaluation procedure are compared with those obtained by X-ray stress-gradient analysis performed on the basis of the sin2ψ method.


1993 ◽  
Vol 8 (4) ◽  
pp. 214-215 ◽  
Author(s):  
T. Wieder

Near-surface triaxial strain/stress states in polycrystalline solids are required for a full tensorial treatment including all elements of the strain/stress tensor. A possible depth dependency of the strain/stress is at best observed by grazing incidence diffraction in Seemann–Bohlin geometry (SBG). The computer program SBGBBG calculates the full strain/stress tensor from X-ray diffraction data measured either in SBG or in Bragg–Brentano geometry (BBG). At present SBGBBG is applicable only on texture-free materials.


Author(s):  
Fabian Jaeger ◽  
Alessandro Franceschi ◽  
Holger Hoche ◽  
Peter Groche ◽  
Matthias Oechsner

AbstractCold extruded components are characterized by residual stresses, which originate from the experienced manufacturing process. For industrial applications, reproducibility and homogeneity of the final components are key aspects for an optimized quality control. Although striving to obtain identical deformation and surface conditions, fluctuation in the manufacturing parameters and contact shear conditions during the forming process may lead to variations of the spatial residual stress distribution in the final product. This could lead to a dependency of the residual stress measurement results on the relative axial and circumferential position on the sample. An attempt to examine this problem is made by the employment of design of experiments (DoE) methods. A statistical analysis of the residual stress results generated through X-Ray diffraction is performed. Additionally, the ability of cold extrusion processes to generate uniform stress states is analyzed on specimens of austenitic stainless steel 1.4404 and possible correlations with the pre-deformed condition are statistically examined. Moreover, the influence of the coating, consisting of oxalate and a MoS2 based lubricant, on the X-Ray diffraction measurements of the surface is investigated.


2014 ◽  
Vol 996 ◽  
pp. 128-134 ◽  
Author(s):  
Youichi Saito ◽  
Shunichiro Tanaka

The residual stress tensor for cracked austenitic stainless steel was measured by a two-dimensional X-ray diffraction method. Higher von Mises equivalent stress concentrations, attributed to hot crack initiation, were obtained at both crack ends. The stress of 400 MPa at the crack end in the columnar grain region was about two-fold larger than that of 180 MPa in the equiaxed grain region. This difference was caused by a depression in the cast slab.


2010 ◽  
Vol 652 ◽  
pp. 37-43 ◽  
Author(s):  
Jeremy Epp ◽  
Thomas Hirsch ◽  
Martin Hunkel ◽  
Robert C. Wimpory

The present work has been executed within the framework of the collaborative research center on Distortion Engineering (SFB 570) in order to evaluate the residual stress state of a disc after carburizing and quenching as well as to validate a simulation procedure. The combined use of X-ray and neutron diffraction analysis provided information about the residual stress states in the whole cross section. However, the stress free lattice spacing d0 for the neutron diffraction experiments is problematic and induces systematic uncertainties in the results and the application of a force balance condition to recalculate d0 might be a solution for improving the reliability of the results. Comparison of experimental results with simulation showed that an overall satisfying agreement is reached but discrepancies are still present.


2006 ◽  
Vol 524-525 ◽  
pp. 755-760 ◽  
Author(s):  
M. Belassel ◽  
Eliane Bocher ◽  
J. Pineault

To enhance the fatigue resistance of mechanical components, different surface treatment processes are often applied to put the near surface layer into compression. Surface treatment processes are typically associated with deformation and work-hardening of the material. When applying x-ray diffraction techniques to the characterization of such surfaces, the work-hardening will cause the x-ray diffraction peak width to increase. When peak widths reach high values, the peak tail may extend beyond the active area or window of the multichannel x-ray detector, in which case the peak is truncated. Subsequent analytical treatment of broad diffraction peaks is troublesome and advanced numerical methods are required to accurately determine the peak position. The following work indicates that when a wider detector is used it is possible to collect the full, non-truncated peak, determine the peak position with a high level of confidence and subsequently, to calculate the residual stress with much improved repeatability and reproducibility.


1993 ◽  
Vol 324 ◽  
Author(s):  
Victor S. Wang ◽  
Richard J. Matyi ◽  
Karen J. Nordheden

AbstractTriple crystal x-ray diffraction (TCXD) is a non-destructive structural characterization tool capable of the separation and direct observation of the dynamic (perfect crystal) and the kinematic (imperfect crystal) components of the total intensity diffracted by a crystal. Specifically, TCXD can be used to measure the magnitude of the diffuse scattering arising from defects in the crystal structure in the immediate vicinity of a reciprocal lattice point. In this study, the effects of BC13 reactive ion etching (RIE) on the near-surface region of GaAs were investigated by analyzing the changes in the diffuse scattering using both the symmetric 004 reflection as well as the highly asymmetric and more surface sensitive 113 reflection. While the results from the 004 reflections revealed little difference between the unetched and the BC13-etched samples, maps of the diffracted intensity around the 113 reflections showed an unexpected and reproducible decrease in the extent of the diffuse scattering in the transverse direction (perpendicular to the < 113 > direction) as the RIE bias voltage was increased. This decrease suggests that the degree of etch damage induced in the GaAs near-surface region is reduced with increasing bias voltage and ion energy. Additionally, the symmetry and orientation of the kinematic scattering was altered. Possible mechanisms for these results willbe discussed.


2002 ◽  
Vol 753 ◽  
Author(s):  
D. Y. Lee ◽  
M. L. Santella ◽  
I. M. Anderson ◽  
G. M. Pharr

ABSTRACTSpecimens of the cast Ni3Al alloy IC221M were annealed in air at 900°C to examine the effects of oxidation and thermal aging on the microstructure. The alloy is comprised of a dendritically solidified γ-γ′ matrix containing γ+Ni5Zr eutectic colonies in the interdendritic regions. Microstructures of aged specimens were examined by optical microscopy and energy dispersive X-ray (EDX) spectrum imaging in the scanning electron microscope (SEM). Two primary changes in the microstructures were observed: (1) there is considerable homogenization of the cast microstructures with aging, and (2) the volume fraction of the γ+Ni5Zr eutectic decreases. Oxidation products were identified using x-ray diffraction and EDX spectrum imaging with multivariate statistical analysis (MSA). During the initial stages of oxidation, the first surface oxide to form is mostly NiO with small amounts of Cr2O3, ZrO2, NiCr2O4, and θ-Al2O3. Initially, oxidation occurs primarily in the interdendritic regions due to microsegregation of alloying elements during casting. With further aging, a continuous film of α-Al2O3 forms immediately beneath the surface that eventually evolves into a double layer of α-Al2O3 and NiAl2O4. Although these oxides are constrained to the near surface region, others penetrate to greater depths facilitated by oxidation of the γ+Ni5Zr eutectic colonies. These oxides appear in the microstructure as long, thin spikes of ZrO2 surrounded by a thin sheath of Al2O3.


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