Effect of Detector Width and Peak Location Technique on Residual Stress Determination in Case of Work-Hardened Materials

2006 ◽  
Vol 524-525 ◽  
pp. 755-760 ◽  
Author(s):  
M. Belassel ◽  
Eliane Bocher ◽  
J. Pineault
Keyword(s):  
Residual Stress ◽  
Surface Treatment ◽  
Work Hardening ◽  
Peak Position ◽  
X Ray Diffraction ◽  
Analytical Treatment ◽  
Near Surface ◽  
X Ray ◽  
Treatment Processes ◽  
High Level

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.

Measuring the Variation of Residual Stress with Depth: A Validation Exercise for Fine Incremental Hole Drilling

2006 ◽  
Vol 524-525 ◽  
pp. 531-537 ◽  
Author(s):  
A. Tony Fry ◽  
Jerry D. Lord
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Hole Drilling ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
Near Surface ◽  
X Ray ◽  
Treatment Processes ◽  
Incremental Hole Drilling ◽  
Significant Interest

Hole drilling along with X-Ray diffraction, is one of the most widely used techniques for measuring residual stress, but the conventional approach is limited in the near surface detail that can be resolved. Because of concerns regarding the levels of induced residual stress that might develop during machining and surface treatment processes, there is significant interest in developing a technique that can obtain near surface residual stress information by the application of fine increment hole drilling. Through a cross comparison with X-ray diffraction and neutron diffraction the procedure of fine incremental drilling has been validated, and the advantages of this technique demonstrated.

scholarly journals Investigations on Residual Stresses within Hot-Bulk-Formed Components Using Process Simulation and the Contour Method

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 566
Author(s):  
Bernd-Arno Behrens ◽  
Jens Gibmeier ◽  
Kai Brunotte ◽  
Hendrik Wester ◽  
Nicola Simon ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Process Simulation ◽  
Hot Forming ◽  
Contour Method ◽  
Stress Profile ◽  
X Ray Diffraction ◽  
Forming Process ◽  
Near Surface ◽  
X Ray

Residual stresses resulting from hot-forming processes represent an important aspect of a component’s performance and service life. Considering the whole process chain of hot forming, the integrated heat treatment provided by a defined temperature profile during cooling offers a great potential for the targeted adjustment of the desired residual stress state. Finite element (FE) simulation is a powerful tool for virtual process design aimed at generating a beneficial residual stress profile. The validation of these FE models is typically carried out on the basis of individual surface points, as these are accessible through methods like X-ray diffraction, hole-drilling, or the nanoindentation method. However, especially in bulk forming components, it is important to evaluate the quality of the model based on residual stress data from the volume. For these reasons, in this paper, an FE model which was already validated by near surface X-ray diffraction analyses was used to explain the development of residual stresses in a reference hot forming process for different cooling scenarios. Subsequently, the reference process scenarios were experimentally performed, and the resulting residual stress distributions in the cross-section of the bulk specimens were determined by means of the contour method. These data were used to further validate the numerical simulation of the hot forming process, wherein a good agreement between the contour method and process simulation was observed.

X-ray diffraction at constant penetration depth – a viable approach for characterizing steep residual stress gradients

2008 ◽  
Vol 41 (2) ◽  
pp. 377-385 ◽  
Author(s):  
Thomas Erbacher ◽  
Alexander Wanner ◽  
Tilmann Beck ◽  
Otmar Vöhringer
Keyword(s):  
Residual Stress ◽  
Penetration Depth ◽  
Ground Surface ◽  
Shear Stresses ◽  
X Rays ◽  
X Ray Diffraction ◽  
Machined Surface ◽  
Near Surface ◽  
X Ray ◽  
Surface Residual Stresses

The experimental analysis of near-surface residual stresses by X-ray diffraction methods is based on measuring the spacings of lattice planes while the inclination ψ with respect to the surface plane is changed stepwise. A characteristic feature of conventional techniques is that the penetration depth of the X-rays is altered as inclination is varied. By simultaneously varying three different goniometer angles in a particular fashion, both the penetration depth and the measuring direction can be held constant while ψ is varied. Thus the normal and shear stresses can be derived from the sin2ψ plots by means of standard evaluation procedures developed for gradient-free stress states. The depth profile of residual stress is then obtainedviaLaplace transformation of the results from several stress measurements carried out at different penetration depths. In the present paper, the feasibility of this experimental approach for characterizing the strongly graded, non-equiaxed stress state existing at a machined surface is demonstrated. The results from constant-penetration-depth measurements on the ground surface of an engineering ceramic are compared with those from conventional sin2ψ measurements.

Modification of ZnO Layers by Molecular Adsorbates During Electrochemical Deposition

2006 ◽  
Vol 957 ◽  
Author(s):  
Thomas Loewenstein ◽  
Christian Neumann ◽  
Bruno K. Meyer ◽  
Tsukasa Yoshida ◽  
Derck Schlettwein
Keyword(s):  
Peak Position ◽  
Zinc Salt ◽  
Eosin Y ◽  
X Ray Diffraction ◽  
Intensity Pattern ◽  
X Ray ◽  
Molecular Adsorbates ◽  
Nucleation Sites ◽  
High Level ◽  
Crystalline Domains

ABSTRACTZnO and ZnO/EosinY hybrid materials were electrodeposited from aqueous zinc salt solutions on (0001) GaN and on (0001) ZnO. Crystalline ZnO was deposited as proven by X-ray diffraction (XRD). The intensity pattern for ZnO/EosinY showed a preferential orientation with the c- plane of ZnO parallel to GaN (0001) or ZnO (0001). XRD rocking curves with FWHM=0.25° indicated a high level of in-plane orientation of the deposited ZnO crystalline domains. The peak position of (0002) ZnO was shifted by 2Θ=1.3°. This difference and the corresponding simultaneous shift of (0004) ZnO were explained by a lattice expansion by 3.6 % in the c- direction. This clearly indicated the strong influence of the Eosin Y molecules adsorbed during the electrodeposition of ZnO. Scanning electron microscopy (SEM) revealed the formation of domains with different crystal sizes pointing at a varying density of nucleation sites on the substrate.

Micro-slotting technique for reliable measurement of sub-surface residual stress in Ti-6Al-4V

2018 ◽  
Vol 53 (6) ◽  
pp. 389-399 ◽  
Author(s):  
Elizabeth Burns ◽  
Joseph Newkirk ◽  
James Castle
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Image Correlation ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
Near Surface ◽  
X Ray ◽  
Measurement Volume ◽  
Surface Residual Stresses

Micro-slotting, a relaxation residual stress measurement technique, has recently been shown to be an effective method for measuring local residual stresses in a variety of materials. The micro-slotting method relies on a scanning electron microscope–focused ion beam system for milling and imaging, digital image correlation software to track displacements due to residual stress relaxation after milling, and finite element analysis for displacement–stress correlation and calculation of the original stress state in the imaged region. The high spatial resolution of the micro-slotting method makes it a promising technique for obtaining near-surface residual stress data in Ti-6Al-4V components for input into fatigue life models and crack growth simulations. However, use of the micro-slotting method on this alloy has yet to be evaluated against more established measurement techniques. In this study, spatially resolved sub-surface residual stress measurements were obtained on shot peened and low-stress surface-machined Ti-6Al-4V planar coupons using the micro-slotting method and were compared to measurements obtained using the conventional X-ray diffraction depth profiling technique. The sub-surface measurements were in good agreement for the shot peened sample. Observed differences in the measured near-surface residual stresses on the surface-machined sample were attributed to the larger measurement volume of the X-ray diffraction method, suggesting that the micron-sized measurement volume of the micro-slotting method may be more suitable for capturing shallow stress profiles and steep stress gradients. Prior to performing the micro-slotting measurements, finite element modeled displacements were used to verify the measurement procedure and to address uncertainties in the milled slot geometries. The results of this study demonstrated the validity of the micro-slotting procedure and established the technique as a reliable method for measuring sub-surface residual stresses in Ti-6Al-4V.

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

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.

Residual Stress Depth Profiling on Ground and on Polished Surfaces of an Al2O3/SiC(w) Composite

1995 ◽  
Vol 39 ◽  
pp. 371-380
Author(s):  
X. Zhu ◽  
P. Predecki ◽  
M. Eatough ◽  
R. Goebner
Keyword(s):  
Residual Stress ◽  
Depth Profiling ◽  
Grazing Incidence ◽  
Inversion Method ◽  
Laplace Method ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
Near Surface ◽  
X Ray ◽  
Stress Components

This study uses the asymmetric grazing incidence x-ray diffraction (GIXD) method and related z-profile retrieval techniques to study the near surface residual stress depth proflles on ground and on polished surfaces of hot-pressed Al2O2SiC(w) composite specimen. The z-profiles of stress components σ11, σ22 and σ33 of the Al2O3 matrix were obtained by using the numerical inversion method as well as the inverse Laplace method. Both τ- and z-profiles of residual stresses are presented.

Sign in / Sign up

Export Citation Format

Share Document