X-Ray Diffraction Determination of Metallurgical Damage in Turbo Blower Rotor Shafts

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.

Download Full-text

Comparison of the hole-drilling and X-ray diffraction methods for measuring the residual stresses in shot-peened aluminium alloys

The Journal of Strain Analysis for Engineering Design ◽

10.1243/030932405x7791 ◽

2005 ◽

Vol 40 (2) ◽

pp. 199-209 ◽

Cited By ~ 22

Author(s):

V Fontanari ◽

F Frendo ◽

Th Bortolamedi ◽

P Scardi

Keyword(s):

Residual Stress ◽

Plastic Deformation ◽

Surface Layer ◽

Hole Drilling ◽

X Ray Diffraction ◽

Residual Stress Field ◽

X Ray ◽

Sources Of Uncertainty ◽

Stress Profiles ◽

Good Agreement

The incremental blind hole-drilling and the X-ray diffraction methods were used to measure the residual stress field introduced by shot peening in aluminium alloy 6082-T5 plates. Two peening treatments were selected to produce different depth extensions and peak values arising from different extents of plastic deformation in the surface layer. The results are discussed considering the various sources of uncertainty; in addition to the measuring technique, the effects of the surface treatment that usually induces a strong plastic deformation in the surface layer resulting in material work hardening and worsening of the surface morphology were considered. The residual stress profiles determined by the two methods showed quite good agreement for the two conditions, as regards the values both of the compressive peak and of the penetration depth. The present results provide mutual confirmation of the effectiveness of the two methods for the study of this class of materials.

Download Full-text

An Expert System for the Validation and Interpretation of X-ray Residual Stress Data

Advances in X-ray Analysis ◽

10.1154/s0376030800014919 ◽

1990 ◽

Vol 34 ◽

pp. 601-610 ◽

Cited By ~ 4

Author(s):

Marc Tricard ◽

Robert W. Hendricks ◽

Marc Guillot

Keyword(s):

Residual Stress ◽

Expert System ◽

X Ray Diffraction ◽

Database Access ◽

X Ray ◽

Know How ◽

Computer Assistance ◽

Technical Features ◽

Non Destructive

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.

Download Full-text

A powder neutron and X-ray diffraction determination of the structure of Ba3Ta2ZnO9: an investigation of perovskite phases in the system Ba–Ta–Zn–O and the preparation of Ba2TaCdO5.5and Ba2CeInO5.5

Acta Crystallographica Section B ◽

10.1107/s0567740876004718 ◽

1976 ◽

Vol 32 (4) ◽

pp. 1083-1087 ◽

Cited By ~ 75

Author(s):

A. J. Jacobson ◽

B. M. Collins ◽

B. E. F. Fender

Keyword(s):

X Ray Diffraction ◽

X Ray ◽

Diffraction Determination

Download Full-text

Revision and extension of the standard laboratory technique for X-ray diffraction measurement of residual stress gradients

Journal of Applied Crystallography ◽

10.1107/s0021889807022935 ◽

2007 ◽

Vol 40 (4) ◽

pp. 675-683 ◽

Cited By ~ 12

Author(s):

Cristy L. Azanza Ricardo ◽

Mirco D'Incau ◽

Paolo Scardi

Keyword(s):

Residual Stress ◽

Hole Drilling ◽

Al Alloy ◽

Diffraction Measurement ◽

X Ray Diffraction ◽

Surface Residual Stress ◽

X Ray ◽

Stress Gradients ◽

Layer Removal ◽

Removal Technique

A new procedure is proposed to determine sub-surface residual stress gradients by laboratory X-ray diffraction measurements at different depths using a chemical layer-removal technique. The standard correction algorithm for stress relaxation due to layer removal is improved by including corrections for X-ray absorption, and by the addition of constraints imposed by the mechanical equilibrium conditions. Besides correcting the data,i.e.providing more reliable through-thickness residual stress trends, the proposed procedure also provides an elastically compatible and plausible estimate of the residual stress inside the component, well beyond the measured region. The application of the model is illustrated for a set of Al-alloy components shot-peened at different Almen intensities. Results are compared with those given by `blind hole drilling', which is an independent and partly destructive method.

Download Full-text

Standardisation of X-Ray Powder Diffraction Methods

Materials Science Forum ◽

10.4028/www.scientific.net/msf.443-444.31 ◽

2004 ◽

Vol 443-444 ◽

pp. 31-34

Author(s):

Giovanni Berti ◽

Rob Delhez ◽

S. Norval ◽

B. Peplinski ◽

E. Tolle ◽

...

Keyword(s):

Technical Committee ◽

Non Destructive Testing ◽

X Ray Diffraction ◽

Destructive Testing ◽

X Ray ◽

Standard Documents ◽

And Control ◽

Non Destructive ◽

Research Centres

This paper outlines the standardisation process for the XRPD method that is currently being considered by a Working Group (WG10) of Technical Committee 138 "Non-destructive Testing" of the European Committee for Standardisation CEN. Several Standard Documents are on the verge of being released. These documents concern the general principles of (X-ray) diffraction, its terminology, and the basic procedures applied. Another document concerns the instruments used and it offers procedures to characterise and control the performance of an X-ray diffractometer properly. It is intended to issue Standard Documents on specific methods, e.g. determination of residual stresses. In fact work is in progress on this subject. The Standard Documents can be used by industry, government organisations, and research centres with activities related to safety, health and the environment, as well as for educational purposes.

Download Full-text