Recent x-ray diffraction studies of metal fatigue in Japan

1975 ◽  
Vol 10 (1) ◽  
pp. 32-41 ◽  
Author(s):  
K Tanaka

This paper describes results of several recent studies, carried out in Japan, on metal-fatigue problems using X-ray diffraction techniques. The subjects covered are the effect of residual stress on fatigue strength, non-destructive detection of fatigue damage from information supplied by X-ray diffraction, and X-ray microbeam analysis of stress and strain near the tips of fatigue cracks and fracture surfaces. The usefulness of the X-ray approach to fatigue problems is emphasized and possible future developments are suggested.

1988 ◽  
Vol 142 ◽  
Author(s):  
John F. Porter ◽  
Dan O. Morehouse ◽  
Mike Brauss ◽  
Robert R. Hosbons ◽  
John H. Root ◽  
...  

AbstractStudies have been ongoing at Defence Research Establishment Atlantic on the evaluation of non-destructive techniques for residual stress determination in structures. These techniques have included neutron diffraction, x-ray diffraction and blind-hole drilling. In conjunction with these studies, the applicability of these procedures to aid in metallurgical and failure analysis investigations has been explored. The x-ray diffraction technique was applied to investigate the failure mechanism in several bent turbo blower rotor shafts. All examinations had to be non-destructive in nature as the shafts were considered repairable. It was determined that residual stress profiles existed in the distorted shafts which strongly indicated the presence of martensitic microstuctures. These microstructures are considered unacceptable for these shafts due to the potential for cracking or in-service residual stress relaxation which could lead to future shaft distortion.


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

2006 ◽  
Vol 524-525 ◽  
pp. 229-234
Author(s):  
M. Belassel ◽  
J. Pineault ◽  
M.E. Brauss

Although x-ray diffraction techniques have been applied to the measurement of residual stress in the industry for decades, some of the related details are still unclear to many production and mechanical testing engineers working in the field. This is because these details, specifically those associated with the transition between diffraction and mechanics, are not always emphasized in the literature. This paper will emphasize the appropriate calculation methods and the steps necessary to perform high quality residual stress measurements. Additionally, details are given regarding the difference between mechanical and x-ray elastic constants, as well as the true meaning of stress and strain from both diffraction and strain gage point of view. Cases where the material is subject to loading above the yield limit are also included.


2012 ◽  
Vol 256-259 ◽  
pp. 1537-1541
Author(s):  
G.Paolo Marconi ◽  
Fabio Remondino ◽  
Belén Jiménez Fenández-Palacios ◽  
Marco Cozzini

The main aim of this paper is to describe the results obtained applying a new methodology developed in order to assess the presence of overloaded areas in steel bridges. The methodology is based on the principle that if the load applied (also just once) in a particular area is higher than the yield strength, it changes the residual stress in this area, inducing a different value of stress if compared with the other areas not overloaded. Using X-Ray diffraction it is possible to detect the value of residual stress on the surface of metals, also in small areas, in a non-destructive way. Therefore this technology is used to detect the presence of overloaded areas on steel bridges. As the areas sampled from X-Ray diffraction are very small (1-2 millimeters of diameter) compared with the dimensions of a bridge, it is necessary to know exactly the position of the areas subjected to the maximum load during the life of the bridge. For this reason FEM analysis are previously conducted in order to evaluate maximum load regions. The construction drawings necessary to perform the FEM analysis are not always available, especially for old bridges, therefore reality-based 3D models are created this problem. Such method is also useful by itself, as beside providing suitable drawings for the FEM analysis, it allows to quickly identify possible large deformations of the bridge structure.


1990 ◽  
Vol 34 ◽  
pp. 601-610 ◽  
Author(s):  
Marc Tricard ◽  
Robert W. Hendricks ◽  
Marc Guillot

AbstractAlthough widely recognized in the research community as one of the most accurate non-destructive methods for the determination of . residual stress in polycrystalline structural materials, x-ray diffraction has not been widely adopted in the field. This is partly due to the fact that such measurements require, most often, a well trained user with knowledge in both materials and mechanical sciences in addition to the specific know-how of the instrument. We believe that computer assistance could contribute to the promotion of this technique by increasing the productivity and accuracy of these measurements. We have developed a prototype expert system, using Nexpert Object's shell, to assist a non-trained operator in the validation and interpretation of X-ray diffraction residual stress data.The present work describes this prototype which has been designed to confirm the feasibility of the concept. Its knowledge base contains relevant examples of the rules necessary for data validation. The prototype has also confirmed most of the concepts required for the implementation of a full-scale version by evaluating all of the major technical features such as graphics representation, external routines and database access.


2015 ◽  
Vol 2 (1) ◽  
pp. 22 ◽  
Author(s):  
P. Ganesh ◽  
D. C. Nagpure ◽  
Rakesh Kaul ◽  
R. K. Gupta ◽  
L. M. Kukreja

Non-destructive characterization of surface microstructure of an engineering component is an important parameter to assess its fitness to function in the given service conditions. The paper describes various case studies performed in authors’ laboratory involving use of portable X-ray diffraction based residual stress analysis system to examine and understand the micro-structural state of the investigated surface. A significant decrease in full width at half maximum (FWHM) of gamma(311) diffraction peak from about 4.2° in the cold worked state to about 2.5° in the annealed/surface melted state was recorded for austenitic stainless steel. In case of 0.4% carbon steel there is sharp increase in FWHM of alpha(211) diffraction peak from about 2° in the as received condition to about 5-6° in the laser hardened condition. Crystallographic texture developed during electro-plating of chromium on stainless steel, could be detected from the strong intensity of alpha (211) peak of chromium at about 19° to the surface normal with respect to all other X-ray inclination angles (ѱ) during residual stress measurement. The results show that FWHM and intensity variation of the diffraction peak are two sensitive parameters for characterization of surface microstructure. Change in FWHM has been used to detect machining-induced cold deformation and evolution of re-crystallized grains in austenitic stainless steel and formation of hard martensite in laser transformation hardened ferritic steel. Variation in the intensity of diffracted peak with respect to X-ray inclination angle provided valuable information regarding crystallographic texture in hard chrome plated deposits.


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