Journal articles: 'X-ray elastic constant'

1

Lundberg, Mattias, Jonas Saarimäki, Johan J. Moverare, and Ru Lin Peng. "Effective X-ray elastic constant of cast iron." Journal of Materials Science 53, no. 4 (October 12, 2017): 2766–73. http://dx.doi.org/10.1007/s10853-017-1657-6.

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Ejiri, Shouichi, Toshihiko Sasaki, and Yukio Hirose. "Residual Stress Analysis of Textured Materials by X-Ray Diffraction Method." Materials Science Forum 706-709 (January 2012): 1673–78. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.1673.

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The residual stress measurement by the conventional X-ray diffraction was formulated on the assumption that a specimen from polycrystalline materials was quasi-isotropic and homogeneous, and the stress was biaxial and almost constant within the X-ray penetration depth. Therefore, it was not available to analyze the stress state of the textured materials by the conventional measurement as a general rule. In resent years, advanced methods have been proposed for the X-ray stress measurement of textured materials. In some methods, it is assumed that the X-ray elastic constant is derived from the crystallite orientation distribution function of textured materials for solving the first anisotropic problem. However, there is a nonlinear problem in the stress analysis from the measured lattice strain. In present study, the X-ray elastic constants were averaged as the expected value around the normal direction of the X-ray diffraction in a similar way. A stress analysis was proposed by differential calculus of the X-ray elastic constant in order to the avoidance of nonlinear problem. The stress analysis was applied to residual stress measurements of a titanium carbide coating film with preferred orientation and a cold-rolled steel with texture. The calculated values of the X-ray elastic constants showed the linearity on some condition for the film. The X-ray stress determination was carried out by the fitting the gradients of the measured lattice strain.

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Kurita, Masanori. "Standard Deviations in X-Ray Stress and Elastic Constants Due to Counting Statistics." Advances in X-ray Analysis 32 (1988): 377–88. http://dx.doi.org/10.1154/s0376030800020681.

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AbstractX-ray diffraction can be used to nondestructively measure residual stress of polycrystalline materials. In x-ray stress measurement, it is important to determine a stress constant experimentally in order to measure the stress accurately. However, every value measured by x-ray diffraction has statistical errors arising from counting statistics. The equations for calculating the standard deviations of the stress constant and elastic constants measured by x-rays are derived analytically in order to ascertain the reproducibility of the measured values. These standard deviations represent the size of the variability caused by counting statistics, and can be calculated from a single set of measurements by using these equations. These equations can apply Lu any meuhud for x-ray stress ifiesuremenL. The variances of the x-ray stress and elastic constants are expressed in terms of the linear combinations of the variances of the peak position. The confidence limits of these constants of a quenched and tempered steel specimen were determined by the Gaussian curve method. The 95% confidence limits of the stress constant were -314 ± 25 MFa/deg.

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Teeuw, D. H. J., and J. Th M. De Hosson. "Determination of x-ray elastic constants using an in situ pressing device." Journal of Materials Research 13, no. 7 (July 1998): 1757–60. http://dx.doi.org/10.1557/jmr.1998.0246.

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The experimental determination of x-ray elastic constants are performed by in situ measurements of the dependence of the strain state in selected crystallites for different applied external compressive stresses. The use of compressive applied stresses instead of tensile applied stresses is of interest for x-ray elastic constant determinations for materials which exhibit brittle crack-like behavior, which cannot be loaded to high tensile stresses in, for example, four-point bending devices. The x-ray elastic constants for {146} α–Al2O3 are determined with the pressing device and compared to calculated as well as experimentally determined values which were tested in tensile loading devices.

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Pathak, T. K., J. J. U. Buch, U. N. Trivedi, H. H. Joshi, and K. B. Modi. "Infrared Spectroscopy and Elastic Properties of Nanocrystalline Mg–Mn Ferrites Prepared by Co-Precipitation Technique." Journal of Nanoscience and Nanotechnology 8, no. 8 (August 1, 2008): 4181–87. http://dx.doi.org/10.1166/jnn.2008.an33.

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Nanoparticles having particle size in the range 25–40 nm for compositions x = 0.0, 0.2, 0.4 and 0.5 of MgxMn1−xFe2O4 spinel ferrite system have been prepared by chemical co-precipitation route. The microstructure, infrared spectral and elastic properties have been studied by means of energy dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM), X-ray diffraction (XRD) and infrared spectroscopic (IR) measurements, before (W) and after high temperature annealing A(W). The force constants for tetrahedral and octahedral sites determined by infrared spectral analysis, lattice constant and X-ray density values by X-ray diffraction pattern analysis; have been used to calculate elastic constants. The magnitude of force constant and elastic moduli for nanocrystalline W-samples are found to be larger as compared to coarse grained A(W)-samples. The results have been explained in the light of redistribution of cations and as a result change in mean ionic charge for such cationic sites, elastic energy and grain size reduction effect of Nanoparticles.

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Attar, Fouad, and Thomas Johannesson. "Adhesion and X-ray elastic constant evaluation of CrN coating." Thin Solid Films 258, no. 1-2 (March 1995): 205–12. http://dx.doi.org/10.1016/0040-6090(94)06373-7.

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Kawamura, Yuki, and Yoshiaki Akiniwa. "Measurement of the X-ray Elastic Constants of Amorphous Polycarbonate." Quantum Beam Science 4, no. 4 (October 9, 2020): 35. http://dx.doi.org/10.3390/qubs4040035.

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In polymer materials, residual stress introduced during injection molding affects yield reduction due to deformation during molding and delayed fracture during operation, so the establishment of nondestructive stress evaluation of polymer products is desirable. The X-ray elastic constants of polycarbonate were measured for the purpose of obtaining fundamental data for X-ray stress measurement of amorphous polymer materials. The structural function was obtained from the diffraction data, and the strain measured by X-ray was determined from the shift of the first peak by the Q-space method. The peak position was determined using the pseudo-Voigt function approximation method and the diffraction line width method. The Young’s modulus measured by X-ray obtained by the diffraction line width method was close to the mechanical value. Although these values varied widely, they changed depending on the peak ratio. A simple and practical measurement method directly using the raw profile data was also discussed. The Young’s modulus determined by the diffraction line width method decreased with increasing peak ratio. On the other hand, the values determined by the pseudo-Voigt method were almost constant, irrespective of the peak ratio. The strain calculated by the line width method was determined more accurately than that by the pseudo-Voigt method.

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SUZUKI, Kenji, and Keisuke TANAKA. "Effect of purity on X-ray elastic constant of sintered alumina." Journal of the Society of Materials Science, Japan 37, no. 417 (1988): 586–91. http://dx.doi.org/10.2472/jsms.37.586.

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9

Badawi, F., and P. Villain. "Stress and elastic-constant analysis by X-ray diffraction in thin films." Journal of Applied Crystallography 36, no. 3 (May 20, 2003): 869–79. http://dx.doi.org/10.1107/s0021889803002486.

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Residual stresses influence most physical properties of thin films and are closely related to their microstructure. Among the most widely used methods, X-ray diffraction is the only one allowing the determination of both the mechanical and microstructural state of each diffracting phase. Diffracting planes are used as a strain gauge to measure elastic strains in one or several directions of the diffraction vector. Important information on the thin-film microstructure may also be extracted from the width of the diffraction peaks: in particular, the deconvolution of these peaks allows values of coherently diffracting domain size and microdistortions to be obtained. The genesis of residual stresses in thin films results from multiple mechanisms. Stresses may be divided into three major types: epitaxic stresses, thermal stresses and intrinsic stresses. Diffraction methods require the knowledge of the thin-film elastic constants, which may differ from the bulk-material values as a result of the particular microstructure. Combining an X-ray diffractometer with a tensile tester, it is possible to determine X-ray elastic constants of each diffracting phase in a thin-film/substrate system, in particular the Poisson ratio and the Young modulus. It is important to notice that numerous difficulties relative to the application of diffraction methods may arise in the case of thin films.

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Kurita, Masanori, Ikuo Ihara, and Nobuyuki Ono. "Residual Stress Measurement of Silicon Nitride and Silicon Carbide by X-Ray Diffraction Using Gaussian Curve Method." Advances in X-ray Analysis 32 (1988): 459–69. http://dx.doi.org/10.1154/s0376030800020784.

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The residual stress induced by grinding or some thermal treatment has a large effect on the strength of ceramics. The X-ray technique can be used to nondestructively measure the residual stress in small areas on the surface of polycrystalline materials. The X-ray stress measurement is based on. the continuum mechanics for macroscopically isotropic polycrystalline materials. In this method, the stress value is calculated selectively from strains of a particular diffraction plane in the grains which are favorably oriented for the diffraction. In general, however, the elastic constants of a single crystal depend on the plane of the lattice, since a single crystal is anisotropic, The behavior of the deformation of individual crystals in the aggregate of polycrystalline materials under applied stress has not yet been solved successfully. Therefore, the stress constant and elastic constants for a particular diffracting plane should be determined experimentally in order to determine the residual stress accurately by X-ray diffraction.

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11

Butler, B. D., B. C. Murray, D. G. Reichel, and A. D. Krawitz. "Elastic Constants of Alloys Measured with Neutron Diffraction." Advances in X-ray Analysis 32 (1988): 389–95. http://dx.doi.org/10.1154/s0376030800020693.

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AbstractElastic constants as a function of crystallographic direction have been measured in polycrystalline alloy samples of 17-4PH stainless steel, Ni-Cr-Fe, and Ti-6%AI-4%V using a neutron diffraction technique. The results compare best with the constant stress model of Reuss. It is demonstrated that measurements of stress can be made sampling the bulk of the material using neutrons with an accuracy comparable to more conventional x-ray methods.

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Modi, Kunal B., Suraj J. Shah, Chetan R. Kathad, Devangi K. Sonigra, Hardik P. Parmar, and Kamlakar M. Jadhav. "On the Relationship between Structural-Elastic Properties of Co-Zn Ferrites at 300 K." Advanced Materials Research 1141 (August 2016): 147–52. http://dx.doi.org/10.4028/www.scientific.net/amr.1141.147.

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The structural - elastic properties correlations have been studied for polycrystalline spinel ferrite system, ZnxCo1-xFe2O4, x = 0.0-0.6, at 300 K. The cation distribution formulae determined from X-ray diffraction line intensity calculations are used to calculate bulk modulus (Ko) in particular and Young′s modulus (E0), rigidity modulus (G0), longitudinal modulus (L0) and Lame′s constant (λL0) in general. The longitudinal wave velocity (Vl0) and transverse wave velocity (Vso) computed from empirical relation based on X-ray density and mean atomic weight is used to calculate L0 and G0 respectively. The applicability of the heterogeneous metal mixture rule for theoretical estimation of elastic constants has been tested. The results are compared with elastic moduli determined from conventional ultrasonic pulse transmission technique and causes for the observed difference between the two have been discussed.

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Benediktovich, Andrey, Ilya Feranchuk, and Alex Ulyanenkov. "Calculation of X-Ray Stress Factors Using Vector Parameterization and Irreducible Representations for SO(3) Group." Materials Science Forum 681 (March 2011): 387–92. http://dx.doi.org/10.4028/www.scientific.net/msf.681.387.

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In the presence of texture, the concept of X-ray elastic constants as well as Sin2ψ law is inapplicable and the X-ray stress factors (XSF) connecting average strain and stress have to be used [1-2]. The SO(3) vector parameterization with smart composition law [3-4] proved to be a powerful tool for handling transformations between reference systems used in XSF calculation. Decomposition of the 4-th rank elastic constant tensor on the SO(3) irreducible representations (IR) allows one to highlight the symmetry properties and to separate isotropic and anisotropic parts. Joint use of the vector parameterization and IR decomposition enables to obtain transparent analytical expressions for XSF in case of textures described by preferred spherical/fiber components.

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Waki, Hiroyuki, and Akira Kobayashi. "Residual Stress Characteristics of Plasma Sprayed CoNiCrAlY Coatings by X-Ray Diffraction." Key Engineering Materials 353-358 (September 2007): 495–98. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.495.

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Plasma sprayed CoNiCrAlY coating can prevent oxidation and corrosion of turbine blades in a gas turbine plant. Cracking and delamination of coatings are affected by the residual stresses in the coatings. In this study, the arising mechanism of residual stress in the plasma sprayed coating was discussed. The residual stresses in CoNiCrAlY coatings were measured by X-ray diffraction method. The coatings were deposited by either low pressure plasma spraying (LPPS) or atmospheric plasma spraying (APS). Each elastic constant which was used for determining the X-ray stress constant was mechanically measured by a bending test. Two kinds of substrates were prepared for each coating in order to examine the effect of thermal expansion coefficient of a substrate. Results were as follows. The residual stresses of the coatings on steel substrates were tensile. On the other hand, the residual stresses on stainless substrates were lower than those on steel substrates. Arising mechanism of the residual stresses can be explained by both the linear expansion coefficient and the range of changing temperature. It was also found that the absolute residual stresses were affected by the spraying powder size and increased with a decrease of the spraying powder size. It was principally caused by the difference in the elastic constants.

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Liu, Chun, Jean-Lou Lebrun, and François Sibieude. "An Advanced Technique for High Temperature X-Ray Elastic Constant and Stress Investigations." Advances in X-ray Analysis 36 (1992): 411–22. http://dx.doi.org/10.1154/s0376030800019030.

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AbstractA high temperature in situ X-Tay diffraction (HTXRD) instrument was devised for residual stress (RS) and X-ray elastic constant (XECs) investigations. The aim was to gain a better understanding of the stresses developed during high temperature oxidation, which is essential for the lifetime improvement of refractory alloys. The investigators use sin2ψ method to survey the stress evolution during oxidation in both the scale and the substrate, and differential method to determine the XECs that relate the measured/measurable deformation to the stress state of the materials studied. The stresses on the Ni/NiO system are measured in situ. The XECs are determined on XC75 steel samples. This paper presents the theories of stresses and XECs determined by HTXRD and briefly discusses the experimental results.

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Wohlschlögel, M., W. Baumann, U. Welzel, and Eric J. Mittemeijer. "Mechanical Stress Gradients in Thin Films Analyzed Employing X-Ray Diffraction Measurements at Constant Penetration/Information Depths." Materials Science Forum 524-525 (September 2006): 19–24. http://dx.doi.org/10.4028/www.scientific.net/msf.524-525.19.

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Stress gradients have been investigated employing a measurement strategy for diffraction measurements at constant penetration/information depths. Two examples have been considered: (i) sputter-deposited copper thin films on silicon wafers and (ii) γ’-Fe4N1-x layers on α-Fe substrates obtained by gaseous nitriding. In the Cu thin films rather low tensile stresses, increasing in magnitude with increasing penetration/information depth have been found. An evaluation of the measured lattice strains has been performed on the basis of the f(ψ) method, where the X-ray elastic constants (XEC’s) have been calculated as weighed averages of the corresponding Voigt and Reuss XEC’s and the weighing parameter has been taken as a fitting parameter. This evaluation reveals that the grain interaction changes with increasing penetration/information depth from near-Reuss type towards Neerfeld-Hill type. In the γ’-Fe4N1-x layers stress gradients occur due to surface relaxation near the surface and deeper in the layer due to a nitrogen concentration gradient which is built up during nitriding. First measurements in a laboratory diffractometer show the effect of surface relaxation on the stress-depth profile near the surface. As no single-crystal elastic constants are available for γ’-Fe4N1-x, the mechanical elastic constants have been employed in diffraction stress analysis. The results indicated that single-crystal elastic anisotropy occurs. From the measured data also a concentration – depth profile has been deduced.

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Jo, J., R. W. Hendricks, W. D. Brewer, and Karen M. Brown. "Determination of X-ray Elastic Constants in a Ti-14Al-21Nb Nb Alloy and a Ti-14Al-21Nb/SiC Metal Matrix Composite." Advances in X-ray Analysis 34 (1990): 689–98. http://dx.doi.org/10.1154/s0376030800015007.

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Residual stress values in a material are governed by the measurements of the atomic spacings in a specific crystallographic plane and the elastic constant for that plane. It has been reported that the value of the elastic constant depends on microstructure, preferred orientation, plastic deformation and morphology [1], Thus, the theoretical calculation of the elastic constant may deviate from the intrinsic value for a real alloy.

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HONDA, Kazuo, Takaaki SARAI, and Seizo INOUE. "X-ray elastic constant and stress measurement in metals having a texture. 3rd report Anisotropy of X-ray diffracted intensity." Transactions of the Japan Society of Mechanical Engineers Series A 52, no. 479 (1986): 1691–97. http://dx.doi.org/10.1299/kikaia.52.1691.

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Villain, Pascale, Philippe Goudeau, Pierre Olivier Renault, and K. F. Badawi. "Elastic Constant Measurement in Supported W/Cu Multilayer Thin Films by X-Ray Diffraction." Materials Science Forum 404-407 (August 2002): 791–96. http://dx.doi.org/10.4028/www.scientific.net/msf.404-407.791.

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Nagashima, Shin-ichi, Masaki Shiratori, and Ryuichi Nakagawa. "Estimation of Ahisotropy of X-Ray Elastic Modulus in Steel Sheets." Advances in X-ray Analysis 29 (1985): 21–28. http://dx.doi.org/10.1154/s0376030800010077.

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The oscillation from a linear relation in the 20 vs. sin2ψ diagram has been a most important problem in X-ray stress measurement. There are, therefore, a number of papers concerned with the X-ray elastic constant, lattice strains under stresses and evaluation of stresses of textured materials.The purpose of the present study is to analyze the three-dimensional orientation distribution of steel sheets by means of the Vector method proposed by Ruer and Baro, and to calculate the elastic modulus of textured sheets by means of a finite element method (FEM) using the three-dimensional orientation distribution, and then to calculate the strain/stress ratios vs. the directions defined by the angles between the specimen normal and the normal to the diffracting planes.

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Farrell, S. P., K. J. Avery, and L. W. MacGregor. "Determination of X-Ray Elastic Constants for Q1N Submarine Pressure Hull Steel." Applied Mechanics and Materials 70 (August 2011): 285–90. http://dx.doi.org/10.4028/www.scientific.net/amm.70.285.

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The Canadian Navy has a requirement to conduct on-site accurate residual stress investigations to improve the efficacy of risk assessment and damage tolerance analysis of critical structures. This paper describes the techniques for qualification of the portable miniature X-ray diffractometer (mXRD) for residual stress analysis on Canadian VICTORIA Class submarine (VCS) pressure hulls. The effect that thermomechanical processing has on the X-ray elastic constant (XREC) and resultant stress analysis is discussed. The approach for calibration of the mXRD equipment and calculation of residual stress values from strain measurements is explained. A new methodology for determination of the XREC, based on the ‘multiple angle method’, is presented discussed and applied to describe the stress-strain relation for tempered Q1N steel. This method, which expands on the ASTM standard, examines the change in lattice strain at multiple y angles (∂dfy/∂sin2y) and provides improved statistical error over the ASTM standard. An XREC of 195 ±6 GPa was experimentally determined for Q1N steel using the {211} crystallographic planes of bcc Fe (using Cr Kα radiation) using the multiple angle method.

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KURITA, Masanori. "A statistical analysis of a stress constant and elastic constants in X-ray stress measurements by the fixed time method." Transactions of the Japan Society of Mechanical Engineers Series A 55, no. 511 (1989): 590–97. http://dx.doi.org/10.1299/kikaia.55.590.

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Taisei, Doi, Masayuki Nishida, and Ozaki Junichi. "Residual Stress Measurement of Industrial Polymers by X-Ray Diffraction." Advanced Materials Research 1110 (June 2015): 100–103. http://dx.doi.org/10.4028/www.scientific.net/amr.1110.100.

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In this study, residual stresses in polyamide (PA) materials were measured by the x-ray stress measurement technique. X-ray stress measurement is widely used to measure residual stresses, however, this measurement is not many used in polymeric materials. There are two problems for measuring residual stresses in polymer. Firstly, the diffraction peak from the polymer appears at the low 2θangle region. Thus the measurement accuracy for strains reduces. Secondly, the low 2θangle region is very difficult to use the sin2ψmethod. In this study,Ω-diffractometer with transmission method was used to resolve these problems. The measured data was plotted in thed-sin2ψdiagram, and it was coincident with the linear regression line clearly. X-ray elastic constant (XEC) of PA was estimated from these results.

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Masayuki, Nishida, Hanabusa Takao, and Yasukazu Ikeuchi. "X-Ray Stress Measurement of Fiber Reinforced Plastics Composite Material." Key Engineering Materials 353-358 (September 2007): 2423–26. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2423.

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X-ray stress measurement with sin2ψ method is one of useful tools to detect residual stresses in manufactured products. In this study, the residual stresses in the tungsten fiber reinforced polyethylene composite were examined by X-ray stress measurement technique. The transmission diffraction method was employed in residual stress measurement of polyethylene matrix. The X-ray elastic constant of high density polyethylene (HDPE) which formed matrix of the composite was estimated before residual stress measurement. The results of sin2ψ diagram with transmission method show good linearity under the several tensile loading. After that the residual stresses in the composite were investigated for HDPE matrix phase. From the measurement results, the tensile residual stresses existed in fiber longitudinal direction and compressive ones in transverse direction for HDPE matrix.

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Mazen, S. A., and T. A. Elmosalami. "Structural and Elastic Properties of Li-Ni Ferrite." ISRN Condensed Matter Physics 2011 (January 4, 2011): 1–9. http://dx.doi.org/10.5402/2011/820726.

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Li-Nickel ferrites with the chemical formula () have been prepared by the ceramic method. The spinel structure in homogenous state was realized by X-ray diffraction analysis. The lattice parameter has been determined for each composition and found to be nearly constant over the whole range of Ni concentration (= 0.83 nm ± 0.01). The cation distribution for each composition has been suggested. The experimental and theoretical lattice constants were found to be in good agreement with each other confirming the agreeability of the suggested cation distribution. The analysis of IR spectra indicates the presence of splitting in the absorption band due to the presence of small amounts of Fe2+ ions in the ferrite system. The force constants for tetrahedral and octahedral sites have been determined. Young’s modulus (E), rigidity modulus (G), bulk modulus (B), Debye temperature (), and transverse () and longitudinal () wave velocities have been determined. The variation of elastic moduli with composition has been interpreted in terms of binding forces between the atoms of spinal lattice.

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Iadicola, Mark A., and Thomas H. Gnäupel-Herold. "Effective X-ray elastic constant measurement for in situ stress measurement of biaxially strained AA5754-O." Materials Science and Engineering: A 545 (May 2012): 168–75. http://dx.doi.org/10.1016/j.msea.2012.02.100.

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Lorimer, G. W. "Quantitative X-ray microanalysis of thin specimens in the transmission electron microscope; a review." Mineralogical Magazine 51, no. 359 (March 1987): 49–60. http://dx.doi.org/10.1180/minmag.1987.051.359.05.

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AbstractIn a thin specimen X-ray absorption and fluorescence can, to a first approximation, be ignored and the observed X-ray intensity ratios, IA/IB, can be converted into weight fraction ratios, , can be converted into weight fraction ratios, CA/CB, by multiplying by a constant , by multiplying by a constant kAB;kAB values can be calculated or determined experimentally. The major correction which may have to be made to the calculated weight fraction ratio is for X-ray absorption within the specimen. The activated volume for analysis in a thin specimen is approximately 100 000 × less than in a bulk sample. Beam spreading within the specimen can be estimated using a simple formula based on a single elastic scattering event at the centre of the specimen. Examples are given of the application of the technique to obtain both qualitative and quantitative analyses from thin mineral specimens. The minimum detectable mass and the minimum mass fraction which can be measured using the technique are estimated.

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Jeong, Y., T. Gnäupel-Herold, M. Iadicola, and A. Creuziger. "Uncertainty in flow stress measurements using X-ray diffraction for sheet metals subjected to large plastic deformations." Journal of Applied Crystallography 49, no. 6 (October 27, 2016): 1991–2004. http://dx.doi.org/10.1107/s1600576716013662.

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X-ray diffraction techniques have been developed to measure flow stresses of polycrystalline sheet metal specimens subjected to large plastic deformation. The uncertainty in the measured stress based on this technique has not been quantified previously owing to the lack of an appropriate method. In this article, the propagation of four selected elements of experimental error is studied on the basis of the elasto-viscoplastic self-consistent modeling framework: (1) the counting statistics error; (2) the range of tilting angles in use; (3) the use of a finite number of tilting angles; and (4) the incomplete measurement of diffraction elastic constants. Uncertainties propagated to the diffraction stress are estimated by conducting virtual experiments based on the Monte Carlo method demonstrated for a rolled interstitial-free steel sheet. A systematic report on the quantitative uncertainty is provided. It is also demonstrated that the results of the Monte Carlo virtual experiments can be used to find an optimal number of tilting angles and diffraction elastic constant measurements to use without loss of quality.

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Rabiei, Marzieh, Arvydas Palevicius, Amir Dashti, Sohrab Nasiri, Ahmad Monshi, Andrius Vilkauskas, and Giedrius Janusas. "Measurement Modulus of Elasticity Related to the Atomic Density of Planes in Unit Cell of Crystal Lattices." Materials 13, no. 19 (October 1, 2020): 4380. http://dx.doi.org/10.3390/ma13194380.

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Young’s modulus (E) is one of the most important parameters in the mechanical properties of solid materials. Young’s modulus is proportional to the stress and strain values. There are several experimental and theoretical methods for gaining Young’s modulus values, such as stress–strain curves in compression and tensile tests, electromagnetic-acoustic resonance, ultrasonic pulse echo and density functional theory (DFT) in different basis sets. Apparently, preparing specimens for measuring Young’s modulus through the experimental methods is not convenient and it is time-consuming. In addition, for calculating Young’s modulus values by software, presumptions of data and structures are needed. Therefore, this new method for gaining the Young’s modulus values of crystalline materials is presented. Herein, the new method for calculating Young’s modulus of crystalline materials is extracted by X-ray diffraction. In this study, Young’s modulus values were gained through the arbitrary planes such as random (hkl) in the research. In this study, calculation of Young’s modulus through the relationship between elastic compliances, geometry of the crystal lattice and the planar density of each plane is obtained by X-ray diffraction. Sodium chloride (NaCl) with crystal lattices of FCC was selected as the example. The X-ray diffraction, elastic stiffness constant and elastic compliances values have been chosen by the X’Pert software, literature and experimental measurements, respectively. The elastic stiffness constant and Young’s modulus of NaCl were measured by the ultrasonic technique and, finally, the results were in good agreement with the new method of this study. The aim of the modified Williamson–Hall (W–H) method in the uniform stress deformation model (USDM) utilized in this paper is to provide a new approach of using the W–H equation, so that a least squares technique can be applied to minimize the sources of errors.

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Bargujer, S. S., N. M. Suri, and R. M. Belokar. "X-ray Diffraction Analysis of Severely Cold Deformed Hypereutectoid Steel Wire." Defence Science Journal 65, no. 6 (November 10, 2015): 500. http://dx.doi.org/10.14429/dsj.65.8385.

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<p>Hypereutectoid steel wire rod of diameter 6.40 mm is lead patented in lead bath of an electric powered furnace and then it is cold drawn through converging conical dies in a die sequence up to 2.50 mm diameter. The drawn wires subjected to different true strain are analysed using line profile X-ray diffraction methods. The classical Williamson-Hall plot as well as modified Williamson-Hall plot of drawn wire specimens of different true strain is plotted. The theoretical as well as experimental value of q is evaluated. The q is a parameter which depends up on elastic constant of the crystal and type of dislocations. The changes in nature of dislocations from edge dislocations to screw dislocations are calculated against true strain and are verified by scanned electron microscopy’s micrograph of drawn wire.</p>

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Guo, F. A., V. Ji, M. François, and Y. G. Zhang. "X-ray elastic constant determination and microstresses of α2 phase of a two-phase TiAl-based intermetallic alloy." Materials Science and Engineering: A 341, no. 1-2 (January 2003): 182–88. http://dx.doi.org/10.1016/s0921-5093(02)00243-5.

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Qazi, Waqas M., Olle Ekberg, Johan Wiklund, Rashid Mansoor, and Mats Stading. "Simultaneous X-ray Video-Fluoroscopy and Pulsed Ultrasound Velocimetry Analyses of the Pharyngeal Phase of Swallowing of Boluses with Different Rheological Properties." Dysphagia 35, no. 6 (February 11, 2020): 898–906. http://dx.doi.org/10.1007/s00455-020-10092-4.

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AbstractThe Ultrasound Velocity Profiling (UVP) technique allows real-time, non-invasive flow mapping of a fluid along a 1D-measuring line. This study explores the possibility of using the UVP technique and X-ray video-fluoroscopy (XVF) to elucidate the deglutition process with the focus on bolus rheology. By positioning the UVP probe so that the pulsed ultrasonic beam passes behind the air-filled trachea, the bolus flow in the pharynx can be measured. Healthy subjects in a clinical study swallowed fluids with different rheological properties: Newtonian (constant shear viscosity and non-elastic); Boger (constant shear viscosity and elastic); and shear thinning (shear rate-dependent shear viscosity and elastic). The results from both the UVP and XVF reveal higher velocities for the shear thinning fluid, followed by the Boger and the Newtonian fluids, demonstrating that the UVP method has equivalent sensitivities for detecting the velocities of fluids with different rheological properties. The velocity of the contraction wave that clears the pharynx was measured in the UVP and found to be independent of bolus rheology. The results show that UVP not only assesses accurately the fluid velocity in a bolus flow, but it can also monitor the structural changes that take place in response to a bolus flow, with the added advantage of being a completely non-invasive technique that does not require the introduction of contrast media.

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HONDA, Kazuo, Takaaki SARAI, and Takashi YANO. "X-ray Elastic Constant and Stress Measurement in Metals Having a Texture : 2nd Report, Plastic Deformation and Residual Stress." Bulletin of JSME 28, no. 239 (1985): 784–91. http://dx.doi.org/10.1299/jsme1958.28.784.

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Kumar, M. Suresh, K. Rajesh, G. V. Vijayaraghavan, and S. Krishnan. "Structural and mechanical properties of diglycine perchlorate single crystals." Materials Science-Poland 36, no. 4 (December 1, 2018): 733–38. http://dx.doi.org/10.2478/msp-2018-0086.

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AbstractGood quality diglycine perchlorate (DGPCL) single crystals were grown by slow evaporation solution growth method using the combination of glycine and perchloric acid in the ratio of 2:1. Single crystal X-ray diffraction and mechanical characterization of the grown single crystals of diglycine perchlorate were analyzed in this article. Lattice parameters, space group and crytal system were found from single crystal X-ray diffraction analysis. All the cell parameters and space group are in a good agreement with the reported values. Mechanical properties, such as Vicker’s microhardness number, work hardening index, standard hardness value, yield strength, fracture toughness, brittleness index and elastic stiffness constant values, were determined using Vicker’s microhardness tester.

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Sun, Baoru, and Tongde Shen. "Probing the Deformation Mechanisms of Nanocrystalline Silver by In-Situ Tension and Synchrotron X-ray Diffraction." Metals 10, no. 12 (December 5, 2020): 1635. http://dx.doi.org/10.3390/met10121635.

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The mechanisms responsible for the deformation of nanocrystalline materials are not well understood although many mechanisms have been proposed. This article studies the room-temperature stress-strain relations of bulk nanocrystalline silver deformed in a tension mode at a constant strain rate. Synchrotron X-ray diffraction patterns were gathered from the deformed specimen and used to deduce such structural parameters as the grain size and the density of dislocations, twins, and stacking faults. Our quantitative results indicate that grain growth and twinning occur in the stage of elastic deformation. Detwinning and accumulation of stacking faults occur in the early stage of plastic deformation, where the strength of nanocrystalline silver correlates well with the square root of stacking faults probability. Grain shrinking and generation of statistically stored dislocations occur in the final stage of plastic deformation, where the strength of nanocrystalline silver correlates well with the square root of the density of dislocations (statistically stored and geometrically necessary). Our results suggest that multiple deformation mechanisms such as grain growth, grain shrinking, twinning, detwinning, stacking faults, and dislocations, rather than a single deformation mechanism, occur in the elastic and plastic deformation stages of nanocrystalline silver.

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Prevey, Paul S. "The Use of Person VII Distribution Functions in X-Ray Diffraction Residual Stress Measurement." Advances in X-ray Analysis 29 (1985): 103–11. http://dx.doi.org/10.1154/s037603080001017x.

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AbstractThe fitting of a parabola by least squares regression to the upper portion of diffraction peaks is commonly used for determining lattice spacing in residual stress measurement. When Kα techniques are employed, the presence of the Kα doublet is shown to lead to significant potential error and non- linearities in lattice spacing as a function of Sin2ψ caused by variation in the degree of blending of the doublet. An algorithm is described for fitting Pearson VII distribution functions to determine the position of the Kα component, eliminating errors caused by defocusing of diffraction peaks of intermediate breadth. The method is applied to determine the subsurface residual stress distribution in ground TI-6 AI- 4 V, comparing directly the use of parabolic and Pearson VII peak profiles, and is shown to provide precision better than ± 1%% in elastic constant determination.

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Wohlschlögel, M., U. Welzel, and E. J. Mittemeijer. "Residual stress and strain-free lattice-parameter depth profiles in a γ′-Fe4N1-x layer on an α-Fe substrate measured by x-ray diffraction stress analysis at constant information depth." Journal of Materials Research 24, no. 4 (April 2009): 1342–52. http://dx.doi.org/10.1557/jmr.2009.0153.

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The residual stress and lattice-parameter depth profiles in a γ′-Fe4N1-x layer (6-μm thickness) grown on top of an α-Fe substrate were investigated using x-ray diffraction stress analysis at constant penetration depths. Three different reflections (220, 311, and 222) were recorded at six different penetration depths using three different wavelengths. At each penetration depth, x-ray diffraction stress analysis was performed on the basis of the sin2ψ method. As a result, the residual-stress depth profile was obtained from the measured lattice strains. The lattice spacings measured in the strain-free direction were used to determine the (strain-free) lattice-parameter depth profile. The nitrogen-concentration depth profile in the layer was calculated by applying a relationship between the (strain-free) γ′ lattice parameter and the nitrogen concentration. It was found that the strain-free lattice-parameter depth profile as derived from the 311 reflections is best compatible with nitrogen concentrations at the surface and at the γ′/α interface as predicted on the basis of local thermodynamic equilibrium. It could be shown that the 311 reflection is most suitable for the analysis of lattice-parameter and residual stress depth profiles because the corresponding x-ray elastic constants exhibit the least sensitivity to the type of and changes in grain interaction. The depth-dependence of the grain interaction could be revealed. It was found that the grain interaction changes from Voigt-type near the surface to Reuss-type at the layer/substrate interface.

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AKINIWA, YOSHIAKI. "X-RAY EVALUATION OF DEFORMATION BEHAVIOR OF SPUTTERED Cu THIN FILMS UNDER TENSILE LOADING." International Journal of Modern Physics: Conference Series 06 (January 2012): 497–502. http://dx.doi.org/10.1142/s2010194512003674.

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Tensile tests were carried out for sputtered copper thin films. Thin films were fabricated by RF magnetron sputtering. The target power of the sputtering equipment was set from 10 to 150 W to control the grain size. The grain size increased with increasing target power. The effect of grain size on the deformation behavior under tensile loading was investigated by X-ray method. The changes in the internal stress and the full width at half maximum were measured under tensile loading. The 0.2% proof stress decreased with grain size. For the full width at half maximum, the value was almost constant in the elastic region. When the plastic deformation occurred, the value increased rapidly with applied strain. For the specimen with fine grains, the value returned to the initial value in spite of after large plastic deformation. After tensile loading, many intergranular cracks could be observed on the specimen surface.

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Zhukov, Vladlen V., Denis A. Shcherbakov, Pavel B. Sorokin, and Boris P. Sorokin. "DEPENDENCE OF PHYSICAL PROPERTIES OF PIEZOELECTRIC ALUMINUM-SCANDIUM NITRIDE ON SCANDIUM CONCENTRATION." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 64, no. 6 (May 16, 2021): 95–103. http://dx.doi.org/10.6060/ivkkt.20216406.6384.

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In this work the physical properties of the piezoelectric aluminum-scandium nitride (ASN) solid solution as a function of scandium concentration were studied using the density functional theory and experimental methods. The phase transition from the wurtzite phase to the rock salt phase at a Sc concentration of 43% was shown. The barriers of transformation from the wurtzite phase to the rock salt phase for various Sc concentrations were obtained. The behavior of the ASN piezoelectric constant d33 calculated by the piezoelectric constants e33, e31, and e15 shows a sharp increase with increasing Sc concentration compared to aluminum nitride AlN. The relationship between the increase in the piezoelectric response of ASN and the softening of the lattice, accompanied by a decrease in the main elastic constants C11, C33, C44 and C66, as well as a decrease in the c/a ratio with increasing Sc concentration, is shown. ASN films with a predominance of the crystal orientation (00·2) were obtained experimentally by magnetron sputtering. The structural properties of the films were studied by X-ray diffraction analysis. A comparison of the experimentally obtained dependence of the c/a ratio on the Sc concentration with the theoretical values showed a good correspondence. Studies of the physical properties of ASN thin films were performed using microwave multi-overtone composite resonators on diamond substrates with a longitudinal bulk acoustic wave (BAW) as the operating mode in the range of 0.5 – 20 GHz. The frequency dependences of the Q-factor of BAW-resonators with different ASN films were obtained, and the frequency dependences of the square of the modulus of the form factor as |m|2 were calculated. The dependences of the elastic constant С33 and the piezoelectric constant e33 for the ASN films with different Sc concentrations were calculated. The calculated and measured values of these constants are agreed within the experimental error.

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Kitamura, Masashi, Nishida Masayuki, and Hanabusa Takao. "Residual Stress Measurement Of High Molecular Matter By Transmission X-Ray Diffraction." Materials Science Forum 681 (March 2011): 381–86. http://dx.doi.org/10.4028/www.scientific.net/msf.681.381.

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In this study, the residual stresses in high-density polyethylene (HDPE) were measured using an x-ray stress measurement technique. There have been few reports published of residual stress investigations in polymeric materials by x-ray stress measurements based on conventional x-ray reflection methods. There are two problems associated with this measurement. Firstly, the diffraction peaks of the polymer in the low 2q angle region and therefore the measurement accuracy for strains reduces. Secondly, the low 2q angle region makes it extremely difficult to use the sin2ψmethod. In the present study we tried to use a transmission method for measuring the residual stress in HDPE sample to resolve these problems. The HDPE sample is shaped into thin sheets which have the three kinds of crystallinity degrees. The measured data is fitted with a good linear regression line in a d-sin2ψdiagram and gradient of the regression line corresponded to the applied stress. On the other hand, the results of the residual stress measurement are deeply associated with degrees of the crystallinity in the HDPE material. The quantitative estimation of crystallinity degrees in the HDPE material was accomplished by a sink-float method. The residual stress distributions were discussed between micro-residual stresses in the crystal phase of HDPE with the amorphous phase of it. Finally, x-ray elastic constant (XEC) of HDPE was estimated and the Initial residual stresses were also measured by use of this XEC parameter.

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Banerjee, Sudip, Suswagata Poria, Goutam Sutradhar, and Prasanta Sahoo. "Nanoindentation and Scratch Resistance Characteristics of AZ31–WC Nanocomposites." Journal of Molecular and Engineering Materials 07, no. 03n04 (September 2019): 1950007. http://dx.doi.org/10.1142/s2251237319500072.

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This work examines the effects of WC nanoparticles on nanohardness, elastic modulus and scratch-induced wear behavior of Mg-based metal matrix nanocomposites. Ultrasonic vibrator-equipped stir casting furnace is used to fabricate Mg–WC nanocomposites. Scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDAX) and X-ray diffraction (XRD) are employed to conduct the characterizations of base alloy and Mg–WC nanocomposites. Vickers microhardness tester is used to obtain the microhardness values of the fabricated materials. Nanoindentation tests are performed to find the effect of wt.% of WC on the mechanical properties, i.e., nanohardness and elastic modulus. Nanohardness and elastic modulus present nearly 122% and 169.37% increments, respectively, compared to the base alloy when only 2[Formula: see text]wt.% of WC is present as reinforcement. Scratch tests are performed to find the effects of wt.% of WC and applied load on the scratch-induced wear and coefficient of friction (CoF) of the base alloy and Mg–WC nanocomposites. Wear volume also decreases continuously with increase in the weight percentage of WC in magnesium alloy. The COFs of nanocomposites are almost constant but they are inclined to increase with the increase in wt.% of WC. Finally, SEM micrographs of scratch grooves are analyzed to find the wear mechanisms. Abrasive wear mechanism is found to be the dominant one regarding the scratch of Mg–WC nanocomposites.

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Moyer, James, and Manika Prasad. "Property changes of oil shale during artificial maturation: The Irati Formation from the Paraná Basin, Brazil." GEOPHYSICS 82, no. 6 (November 1, 2017): MR175—MR190. http://dx.doi.org/10.1190/geo2016-0605.1.

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Acquiring elastic property information from oil shale during pyrolysis remains a difficult endeavor. We subject oil shale samples from the Irati Formation in the Paraná Basin, Brazil, to high-temperature, high-pressure hydrous and anhydrous pyrolysis while simultaneously acquiring P- and S-waveform data. We present elastic properties as a function of temperature at constant differential pressure using samples cored in three different directions relative to the bedding plane. Hydrous pyrolysis decreased total organic carbon (TOC) in samples from 25 wt% to 20 wt%, whereas anhydrous pyrolysis had no significant change in TOC. The cores experienced higher strain hysteresis (up to –0.094 residual axial strain) after hydrous pyrolysis compared to after anhydrous pyrolysis ([Formula: see text] residual axial strain). The larger residual strain was accompanied by a larger increase in shear velocity up to 35% after hydrous pyrolysis as compared to the 3% shear velocity increase after anhydrous pyrolysis. The change could be a result of compression and loss of organic content determined at an ambient temperature of 25°C. We quantified sample changes using X-ray computed tomography, scanning electron microscopy, source rock analysis, and X-ray diffraction before and after pyrolysis. Our data on elastic properties and Thomsen’s parameters during pyrolysis can be used to extract material property information useful for improving subsurface well logging and 4D seismic to produce efficiently from oil shale formations.

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Vijayalakshmi, M., C. Yogambal, D. Rajan Babu, and R. Ezhil Vizhi. "Mechanical Studies of Nonlinear Optical γ-Glycine Single Crystal Grown in the Presence of Lithium Nitrate." Advanced Materials Research 584 (October 2012): 145–49. http://dx.doi.org/10.4028/www.scientific.net/amr.584.145.

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Single Crystal of γ-glycine lithium nitrate with non-linear optical material have been grown by slow evaporation method at room temperature. Structural and Crystalline nature of the grown γ-glycine lithium nitrate crystal was confirmed by powder X-ray diffraction technique. UV-Visible transmittance study was performed to analyze optical transparency of γ-glycine crystal and found that the crystal was transparent in the entire visible region. The mechanical properties of the grown crystal was subjected to Vickers hardness test and the Brittleness index (Bi), Fracture toughness (Kc), Elastic stiffness constant (C11) were estimated.

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Rendale, Maruti K., S. N. Mathad, and Vijaya Puri. "Structural, mechanical and elastic properties of Ni0.7−xCoxZn0.3Fe2O4 nano-ferrite thick films." Microelectronics International 34, no. 2 (May 2, 2017): 57–63. http://dx.doi.org/10.1108/mi-02-2016-0009.

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Purpose The present communication aims to investigate the influence of cobalt substitution on the structural, mechanical and elastic properties of nickel–zinc ferrite thick films. The changes observed in the crystallite size (D), lattice constant (a), texture coefficient [TC(hkl)] and mechanical and elastic properties of the thick films due to cobalt substitution have been reported systematically. Design/methodology/approach Ni–Zn ferrites with the stoichiometric formula Ni0.7−xCoxZn0.3Fe2O4 (where, x = 0, 0.04, 0.08, 0.12, 0.16 and 0.20) were synthesized via solution combustion technique using sucrose as the fuel and poly-vinyl-alcohol as the matrix material. The thick films of the ferrites were fabricated on alumina substrates by the screen printing method. The thickness of the films was 25 μm, as measured by the gravimetric method. The thick films were subjected to X-ray diffraction and Fourier transform infrared spectroscopy. Findings The detailed study of variation of lattice parameter (a), sintering density, micro-strain and elastic properties with cobalt (Co+2) substituted was carried out. The remarkable increase in lattice parameter (from 8.369 A° to 8.3825 A°), bulk density and average grain size (69-119 nm) with the cobalt content was due to larger ionic radius of Co2+ compared to Ni2+. Texture analysis [TC(hkl)] reveals all thick films have adequate grain growth in the (311) plane direction. The main absorption bands of spinel ferrite have appeared through infrared absorption spectra recorded in the range of 300-700 cm−1. Originality/value The variation in stiffness constants (for isotropic material, C11 = C12), longitudinal elastic wave (Vl), transverse elastic wave (Vt), mean elastic velocity (VMean), rigidity modulus (G), Poisson’s ratio(s) and Young’s modulus (E) with cobalt (Co+2) composition has been interpreted in terms of binding forces found.

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Akiniwa, Yoshiaki, Tsuyoshi Suzuki, and Keisuke Tanaka. "Evaluation of Deformation Behavior in Cu Thin Film under Tensile and Fatigue Loading by X-Ray Method." Materials Science Forum 524-525 (September 2006): 807–12. http://dx.doi.org/10.4028/www.scientific.net/msf.524-525.807.

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Two kinds of electrodeposited copper foils (thickness is 8 and 20 μm) were loaded statically, and the deformation behavior was observed. In-situ X-ray stress measurement was carried out under tensile loading. Fatigue tests were also conducted to observe the effect of the thickness on the fatigue strength. Change in the line broadening with stress cycles was observed to evaluate the fatigue damage. The tensile strength of 8 μm foil was higher than that of 20 μm foil. When the foils were loaded within elastic region, the stress measured by the X-ray method agreed with applied stress. When the plastic deformation occurred, difference between the measured stress and the applied stress became large. The difference of 20 μm foil was larger than that of 8 μm foil. Fatigue strength of 8 μm foil was also higher than that of 20 μm foil. The value of the full width at half maximum, FWHM, increased rapidly at the first cycle, and then the value became nearly constant. Just before fracture, the value increased again. The change in FWHM corresponded to the change in the accumulated ratchet strain.

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Wan, Fan, Shixiang Zhao, Rongjun Liu, Changrui Zhang, and Thomas J. Marrow. "In situ Observation of Compression Damage in a Three-Dimensional Braided Carbon Fiber Reinforced Carbon and Silicon Carbide (C/C-SiC) Ceramic Composite." Microscopy and Microanalysis 24, no. 3 (June 2018): 227–37. http://dx.doi.org/10.1017/s1431927618000351.

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AbstractDeformation and mechanical damage in a three-dimensional braided carbon fiber reinforced carbon and silicon carbide ceramic composite, subjected to compressive loading, has been studied in situ by laboratory X-ray computed tomography. Dimensional change was measured and damage visualized by digital volume correlation analysis of tomographs. Cracks nucleated from defects within the fiber bundles and tended to propagate along the fiber bundle/matrix interface. For longitudinal compression, parallel to the fiber bundles, the initial elastic modulus decreased with increasing compressive strain while significant transverse tensile strains developed due to distributed cracking. For transverse compression, perpendicular to the fiber bundles, the compressive elastic modulus was effectively constant; the tensile strains developed along the fiber direction were small, whereas macroscopic fracture between the fiber bundles caused very large bulk tensile strain perpendicular to the loading. The observations suggest that the mechanical strength might be improved through control of pre-existing defects and application of stitch fibers in the transverse direction.

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Xu, Jingjing, Maojin Tan, Xiaochang Wang, and Chunping Wu. "Predicting acoustic-wave velocities and fluid sensitivity to elastic properties in fractured carbonate formation." Interpretation 5, no. 1 (February 1, 2017): SB69—SB80. http://dx.doi.org/10.1190/int-2016-0067.1.

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Estimation of S-wave velocity is one of the most critical steps for prestack seismic inversion. Based on the petrophysical model of fractured carbonate rocks, theoretical methods are firstly investigated for estimating P- and S-wave velocities in the presence of fractures. Then, the methods of calculating elastic properties in fractured carbonate rocks are discussed. The mineral concentration, total porosity, and fracture porosity from core X-ray diffraction and routine core measurements or log interpretation results are used to estimate the P- and S-wave velocities. In the given carbonate rock model, the elastic properties of carbonate rocks with different porosity and fractures are calculated. Two field tests prove that the proposed new method is effective and accurate. Furthermore, the model is useful for fluid identification, which is one of the most outstanding problems for carbonate reservoir description. The simulation results suggest that the larger the fracture porosity is, the easier fluid typing. In Tahe Oilfield, the elastic properties of different fluid zones indicate that bulk modulus and Young’s modulus are more sensitive to fluid than shear modulus, the Lamé constant, and Poisson’s ratio.

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Pasayat, Shubhra S., Chirag Gupta, Yifan Wang, Steven P. DenBaars, Shuji Nakamura, Stacia Keller, and Umesh K. Mishra. "Compliant Micron-Sized Patterned InGaN Pseudo-Substrates Utilizing Porous GaN." Materials 13, no. 1 (January 4, 2020): 213. http://dx.doi.org/10.3390/ma13010213.

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The compliant behavior of densely packed 10 × 10 µm2 square patterned InGaN layers on top of porous GaN is demonstrated. The elastic relaxation of the InGaN layers is enabled by the low stiffness of the porous GaN under layer. High resolution X-ray diffraction measurements show that upon InGaN re-growths on these InGaN-on-porous GaN pseudo-substrates, not only was the regrown layer partially relaxed, but the degree of relaxation of the InGaN pseudo-substrate layer on top of the porous GaN also showed an increase in the a-lattice constant. Furthermore, methods to improve the surface morphology of the InGaN layers grown by metal-organic chemical vapor deposition (MOCVD) were explored in order to fabricate InGaN pseudo-substrates for future optoelectronic and electronic devices. The largest a-lattice constant demonstrated in this study using this improved method was 3.209 Å, corresponding to a fully relaxed InGaN film with an indium composition of 0.056.

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Aso, Mai, Kanae Ito, Hiroaki Sugino, Koji Yoshida, Takeshi Yamada, Osamu Yamamuro, Shinji Inagaki, and Toshio Yamaguchi. "Thermal behavior, structure, and dynamics of low-temperature water confined in mesoporous organosilica by differential scanning calorimetry, X-ray diffraction, and quasi-elastic neutron scattering." Pure and Applied Chemistry 85, no. 1 (October 31, 2012): 289–305. http://dx.doi.org/10.1351/pac-con-12-06-02.

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Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and quasi-elastic neutron scattering (QENS) measurements have been made at 200~330 K for capillary-condensed water confined in periodic mesoporous organosilica (PMO) materials with the phenyl groups embedded in silica matrix (Ph-PMO; pore diameter 30 Å). The DSC data showed that the capillary-condensed water in Ph-PMO freezes at 228 K. X-ray radial distribution functions (RDFs) showed that the tetrahedral-like hydrogen-bonded structure of water is distorted in Ph-PMO pores, compared with bulk water; however, with lowering temperature the tetrahedral moiety of water is gradually recovered in the pores. Below the freezing point, cubic ice Ic was formed in the Ph-PMO pores. The QENS data showed that the translational diffusion constant and the residence time and the rotational relaxation time of water molecule in Ph-PMO are comparable with those in bulk. The corresponding activation energies suggested that the more hydrophobic the nature of the wall is, the smaller the activation energy of diffusion and rotation of a water molecule; this implies that water molecules confined in the hydrophobic pores are present in the core of the pores, whereas those in the hydrophilic pores strongly interact with the silanol groups.

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Singh, Anand Pal, Connie A. Avramis, John KG Kramer, and Alejandro G. Marangoni. "Algal meal supplementation of the cows' diet alters the physical properties of milk fat." Journal of Dairy Research 71, no. 1 (February 2004): 66–73. http://dx.doi.org/10.1017/s0022029903006642.

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A three-week algal meal supplementation of the cows' basal diet resulted in an increase in the firmness of milk fat crystallized isothermally at 5 °C for 24 h – the apparent elastic constant increased from 100 to 224 N/mm. This was accompanied by a decrease in solid fat content, from 47·7% to 44·4%. The crystallization behaviour of milk fat was also modified significantly. The rate constant of crystallization (Avrami constant) of the enriched milk fat at 19 °C was ∼20 times higher than that of control milk fat. A shorter induction time of nucleation was also observed in the temperature range [20, 27 °C]. These effects were attributed to a higher degree of supersaturation of the enriched milk fat. Enriched milk fat nucleated in a more stable β' polymorphic form at 5 °C, while control milk fat nucleated in the metastable α form, as determined by powder X-ray diffraction and differential scanning calorimetry. Changes in the microstructure of the material were observed by polarized light microscopy at 5 °C. The enriched milk fat displayed a greater amount of crystal clustering than the control. This effect was reflected in a decrease in the box-counting mass fractal dimension (Db) of the fat crystal network from 1·853 to 1·809. The decrease in Db closely predicted the observed 2·2-fold increase in the elastic constant of the fat. These changes in mechanical properties, crystallization behaviour and microstructure were driven by an increase in the 18[ratio ]1trans and a decrease in the 18[ratio ]1cis fatty acid content of the enriched milk fat.

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Journal articles on the topic 'X-ray elastic constant'

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