Assessment of residual strains in mullite/zirconia-toughened alumina composites using X-ray diffraction

1994 ◽  
Vol 13 (18) ◽  
pp. 1354-1356 ◽  
Author(s):  
I. M. Low ◽  
R. D. Skala ◽  
D. Y. Li
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
Alumina Composites ◽  
Residual Strains ◽  
Zirconia Toughened Alumina

Investigation of Residual Strains of the Second Kind in Plastically Deformed Metallic Materials

1994 ◽  
Vol 376 ◽  
Author(s):  
M. Vrána ◽  
P. Klimanek ◽  
T. Kschidock ◽  
P. Lukáš ◽  
P. Mikula
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Stacking Faults ◽  
Metallic Materials ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Diffractometer ◽  
Residual Strains ◽  
Good Agreement

ABSTRACTInvestigation of strongly distorted crystal structures caused by dislocations, stacking-faults etc. in both plastically deformed f.c.c. and b.c.c. metallic materials was performed by the analysis of the neutron diffraction line broadening. Measurements were realized by means of the high resolution triple-axis neutron diffractometer equipped by bent Si perfect crystals as monochromator and analyzer at the NPI Řež. The substructure parameters obtained in this manner are in good agreement with the results of X-ray diffraction analysis.

Residual stresses in a SiC whisker-reinforced alumina composite by high-temperature X-ray diffraction

1994 ◽  
Vol 9 (1) ◽  
pp. 50-53 ◽  
Author(s):  
Benjamin L. Ballard ◽  
Paul K. Predecki ◽  
Camden R. Hubbard
Keyword(s):  
Residual Stress ◽  
Single Crystal Silicon ◽  
Linear Extrapolation ◽  
X Ray Diffraction ◽  
Crystal Silicon ◽  
X Ray ◽  
Fine Grained ◽  
Silicon Carbide Whiskers ◽  
Alumina Composite ◽  
Residual Strains

Residual strains and microstresses are evaluated for both phase of a hot-pressed, fine-grained α-alumina reinforced with 25 wt% (29 vol%) single-crystal silicon carbide whiskers at temperatures from 25 to 1000 °C. The sample was maintained in a nonoxidizing environment while measurements of the interplaner spacing of alumina (146) and SiC (511 + 333) were made using X-ray diffraction methods. The residual strains were profiled at temperature increments of 250 °C from which the corresponding microstresses were calculated. Linear extrapolation of the SiC ε33 profile indicates that the strains are completely relaxed at a temperature of approximately 1470 °C. These residual stress relaxation results suggest that elevated temperature toughness and fracture strength of this composite may result from cooperative mechanisms.

The Meed for Experimentally Determined X-ray Elastic Constants

1976 ◽  
Vol 20 ◽  
pp. 355-367 ◽  
Author(s):  
R. H. Marion ◽  
J. B. Cohen
Keyword(s):  
Residual Stresses ◽  
Elastic Constants ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Strains ◽  
Entire Specimen ◽  
Representative Material

In order to convert residual strains measured by x-ray diffraction techniques into residual stresses, appropriate x-ray elastic constants have to be measured. Since these x-ray elastic constants may depend on the metallurgical state, deformation, and entire specimen history, errors in stress values may result if the constants are not measured for representative material states. In the present work, it is shown that in same cases these errors may be large.

Direct X-Ray Measurement of Residual Strains in Textured Steel

1983 ◽  
Vol 27 ◽  
pp. 197-206
Author(s):  
C. P. Gazzara
Keyword(s):  
Residual Stress ◽  
Crystal Lattice ◽  
Elastic Constants ◽  
Random Distribution ◽  
Elastic Anisotropy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Strains ◽  
Residual Stress Analysis ◽  
Textured Materials

One of the most detrimental effects on the accuracy of an X-ray diffraction residual stress analysis, XRDRSA(l), is found in the examination of textured materials. The degree of elastic anisotropy and texture is in general agreement with the extent of the error in the residual stress. Several approaches have been made to correct for the effects of texture, particularly involving experimental techniques. Reviews of such efforts are given by H. D811e(2), v.M. Hauk﹛3) and G. Maeder, J.L. Lebrun and J.M. Sprauel (4), just to mention a few.A brief chronology of the texture corrections involved in XRDRSA follows. With isotropic materials the d spacing of a crystal lattice, d, is assumed to vary linearly with sin2ψ. With textured materials the d vs sin2ψ relationship is nonlinear. This is due to the anisotropy of the elastic constants and their departure from a random distribution, or taking on a preferred orientation.

Three-dimensional welding residual stresses evaluation based on the eigenstrain methodology via X-ray measurements at the surface

2014 ◽  
Vol 03 (04) ◽  
pp. 1450023
Author(s):  
Masaru Ogawa
Keyword(s):  
Neutron Diffraction ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Strain Gauges ◽  
X Ray Diffraction ◽  
Stress Evaluation ◽  
X Ray ◽  
Residual Strains ◽  
Non Destructive ◽  
Evaluation Accuracy

In order to assure structural integrity for operating welded structures, it is necessary to evaluate crack growth rate and crack propagation direction for each observed crack non-destructively. Here, three dimensional (3D) welding residual stresses must be evaluated to predict crack propagation. Today, X-ray diffraction is used and the ultrasonic method has been proposed as non-destructive method to measure residual stresses. However, it is impossible to determine residual stress distributions in the thickness direction. Although residual stresses through a depth of several tens of millimeters can be evaluated non-destructively by neutron diffraction, it cannot be used as an on-site measurement technique. This is because neutron diffraction is only available in special irradiation facilities. Author pays attention to the bead flush method based on the eigenstrain methodology. In this method, 3D welding residual stresses are calculated by an elastic Finite Element Method (FEM) analysis from eigenstrains which are evaluated by an inverse analysis from released strains by strain gauges in the removal of the reinforcement of the weld. Here, the removal of the excess metal can be regarded as non-destructive treatment because toe of weld which may become crack starters can be eliminated. The effectiveness of the method has been proven for welded plates and pipes even with relatively lower bead height. In actual measurements, stress evaluation accuracy becomes poorer because measured values of strain gauges are affected by processing strains on the machined surface. In the previous studies, the author has developed the bead flush method that is free from the influence of the affecting strains by using residual strains on surface by X-ray diffraction. However, stress evaluation accuracy is not good enough because of relatively poor measurement accuracy of X-ray diffraction. In this study, a method to improve the estimation accuracy of residual stresses in this method is formulated, and it is shown numerically that inner welding residual stresses can be estimated accurately from the residual strains measured by X-ray diffraction.

scholarly journals Study on the Mechanism and Application of Applying Magnetic Barkhausen Noise to Evaluate Dislocation Density and Plastic Deformation

2020 ◽  
Author(s):  
Xueliang Kang ◽  
Shiyun Dong ◽  
Hongbin Wang ◽  
Xiaoting Liu ◽  
Shixing Yan
Keyword(s):  
Plastic Deformation ◽  
Dislocation Density ◽  
Diffraction Method ◽  
Grain Morphology ◽  
Barkhausen Noise ◽  
Magnetic Barkhausen Noise ◽  
X Ray Diffraction ◽  
X Ray ◽  
Texture Characteristics ◽  
Residual Strains

Seven specimens of 45 steel with different residual strains were prepared by homogeneous plastic tensile test. The microstructure of the specimens was observed by scanning electron microscopy and the texture characteristics of the specimens were studied by X-ray diffraction. The results showed that plastic deformation mainly leads to dislocation increment in the microstructure rather than obvious deformed grain morphology, texture and residual stress. Then the dislocation density of each sample was calculated by X-ray diffraction method. The MBN signals of the samples were tested by magnetic Barkhausen noise method and the corresponding RMS (root mean square) values were calculated. The results showed that the dislocation density increases and the RMS value decreases with the increase of plastic deformation magnitude, the phenomenon was explained deeply. By establishing the correlation between dislocation density and RMS value, it was found that there was a good linear relationship between dislocation density and RMS value. According to the formula provided by the fitting curve, the dislocation density can be predicted by measuring the RMS value of any degree of plastic deformation.

scholarly journals High energy white beam x-ray diffraction studies of residual strains in engineering components

2008 ◽  
Author(s):  
S. Y. Zhang ◽  
W. Vorster ◽  
T. S. Jun ◽  
X. Song ◽  
M. Golshan ◽  
...  
Keyword(s):  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
White Beam ◽  
Residual Strains
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