Thermal expansion of cladding tubes and rods made of Zr-1% Nb alloy in the temperature range 293-873 K (20-600°C)based on X-ray and dilatometric measurements

2020 ◽  
pp. 53-65
Author(s):  
M.G. Isaenkova ◽  
◽  
A.V. Tenishev ◽  
Yu.A. Perlovich ◽  
S.D. Stolbov ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Linear Expansion ◽  
Axial Direction ◽  
Internal Stresses ◽  
Layer By Layer ◽  
X Ray ◽  
Temperature Range ◽  
Texture Parameters ◽  
Temperature Dependences ◽  
Expansion Coefficients

The temperature dependences of the periods a and c of the crystal structure of a-Zr and thermal linear expansion coefficients (TLEC) of textured cladding tubes and rods of E110opt Zr-based alloy in the axial direction in the temperature range of 293-873 K (20-600 °С) were determined. On the basis of Kearns’ integral texture parameters for cladding tubes and rods, TLEC values were calculated. The calculated values of the TLEC turned out to be significantly smaller than the values measured by the dilatometric method. Simulation of the process of thermal expansion of goods showed that the observed differences in the calculated and measured values of the TLEC can be due to layer-by-layer texture inhomogeneity of tubes and internal stresses arising between the layers.

Regularities of the thermal expansion of cladding tubes and rods from E110opt alloy in the temperature range 273-1473 K (20-1200°C)

2020 ◽  
Vol 4 ◽  
pp. 51-64
Author(s):  
M.G. Isaenkova ◽  
◽  
A.V. Tenishev ◽  
Yu.A. Perlovich ◽  
S.D. Stolbov ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Phase Transformations ◽  
Orientation Dependence ◽  
Internal Stresses ◽  
Layer By Layer ◽  
Temperature Range ◽  
Heating And Cooling ◽  
Expansion Coefficients ◽  
Analytical Expressions ◽  
Tangential Directions

The regularities of the thermal expansion of cladding tubes and rods from the E110opt alloy, as well as the anisotropy of their thermal properties in the case of layer-by-layer texture inhomogeneity are studied. The thermal linear expansion coefficients (TLEC) of rods and cladding tubes were measured in the axial, radial and tangential directions during heating and cooling in the temperature range of 293-1473 K (20-1200°C). It is shown that as a result of a→b→a phase transformations in the samples, a stable texture of phase transformations is formed which is preserved during subsequent heating and cooling cycles. Analytical expressions are obtained that describe the temperature dependence of the thermal expansion coefficient in the first cycle of heating products from the E110opt alloy, taking into account possible a→b phase transformations and the resulting a-Zr crystal lattice deformation along the a and c axes. It was established that the presence of layer-by-layer inhomogeneity in the samples leads to the appearance of stresses between layers with different crystallographic textures and, as a result, affects the orientation dependence of phase transformations that are sensitive to the stress state in the material. The results obtained indicate the need to take into account the internal stresses arising in textured anisotropic materials during heating and cooling, and to separate the contributions of thermal expansion and plastic deformation when analyzing data from dilatometric measurements of sample sizes.

Effects of Vacancies on the Thermal Expansion of Mercury Indium Telluride Crystals

2010 ◽  
Vol 663-665 ◽  
pp. 1008-1011
Author(s):  
Ling Hang Wang
Keyword(s):  
Thermal Expansion ◽  
Room Temperature ◽  
Linear Expansion ◽  
Semiconductor Material ◽  
X Ray ◽  
Temperature Range ◽  
Vertical Bridgman ◽  
Indium Telluride

The thermal expansion of a novel semiconductor material, mercury indium telluride (MIT) grown by vertical Bridgman (VB) method, was measured from room temperature till 573K by two methods, i.e. Macroscopic dilatometric and X-ray measurements. It is found that the macroscopic expansion is quite different from the expansion of the lattice (micro-expansion). The macroscopic expansion is lower than micro-expansion in the temperature range of 303-425.5K and has a minimum of -0.14% linear expansion, while the macro-expansion becomes larger than micro-expansion in the temperature higher than 425.5K. The former may be due to the effects of the existing neutral vacancies. The latter may result from the influence of thermal-activated vacancies on the lattice.

Polymorphism in Ho2(MoO4)3

2013 ◽  
Vol 28 (S2) ◽  
pp. S33-S40 ◽  
Author(s):  
C. González-Silgo ◽  
C. Guzmán-Afonso ◽  
V. M. Sánchez-Fajardo ◽  
S. Acosta-Gutiérrez ◽  
A. Sánchez-Soares ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Room Temperature ◽  
Linear Expansion ◽  
Negative Thermal Expansion ◽  
Thermal Treatments ◽  
Positive Coefficient ◽  
X Ray ◽  
Expansion Coefficients ◽  
First Time

Two polymorphs of Holmium molybdate, known as β'-phase and γ-phase, were prepared by solid state reaction with different thermal treatments. These polycrystalline samples have been studied for the first time by X-ray thermodiffractometry from room temperature up to 1300 K. We found that the initial β'-phase undergoes a transition to a β-phase and then to a γ-phase. The γ (hydrated)-phase, turns to the γ (dehydrated)-phase and then to the β-phase. Each sequence involves a reversible and an irreversible phase transition for Ho2(MoO4)3. Both polymorphs have remarkable physical properties like nonlinear optics, ferroelectricity and negative thermal expansion. We have calculated the linear expansion coefficients of both phases. We have obtained a positive coefficient for the β'-phase and a negative one for the γ-phase. Moreover, we have made a comparison of the obtained coefficients with previous results for other rare earth molybdates.

Crystal structure and thermal expansion of hexakis(phenylthio)benzene and its CBr4 clathrate

1995 ◽  
Vol 73 (4) ◽  
pp. 513-521 ◽  
Author(s):  
Darek Michalski ◽  
Mary Anne White ◽  
Pradip K. Bakshi ◽  
T. Stanley Cameron ◽  
Ian Swainson
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Neutron Powder Diffraction ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

The crystal structures of hexakis(phenylthio)benzene (HPTB) and its CBr4 clathrate have been determined by single crystal X-ray diffraction data collected at T = 18 °C and refined to final Rw of 0.036 and 0.047, respectively. Pure HPTB is triclinic, space group [Formula: see text] (No. 2), with a = 9.589(2) Å, b = 10.256(1) Å, c = 10.645(2) Å, α = 68.42(1)°, β = 76.92(2)°, γ = 65.52(1)°, and Z = 1. The CBr4 clathrate of HPTB is rhombohedral, space group [Formula: see text] (No. 148), with a = 14.327(4) Å, b = 20.666(8) Å, and Z = 3. The host–guest mole ratio of HPTB–CBr4 is 1:2. Neutron powder diffraction was carried out on powders of both compounds in the temperature range 25 K < T < 295 K. Thermal expansion coefficients were determined for HPTB and HPTB–CBr4 over this temperature range. Keywords: thermal expansion, crystal structure, clathrate.

scholarly journals Temperature Dependences of Structural Parameters of PMN in the Region of Diffuse Phase Transition

2020 ◽  
Vol 329 ◽  
pp. 02037
Author(s):  
Alla Lebedinskaya ◽  
Angela Rudskaya
Keyword(s):  
Diffuse Phase Transition ◽  
Linear Expansion ◽  
Structural Parameters ◽  
Potential Relief ◽  
Abrupt Decrease ◽  
X Ray ◽  
Temperature Range ◽  
Temperature Dependences ◽  
Coefficient Of Linear Expansion ◽  
Diffuse Phase

In this work, we analyzed the structural parameters of the lead magnoniobate sample in the temperature range from 20 ºC to 450 ºC by X- ray structural analysis. It was found that the PMN cubic perovskite cell does not undergo distortions over the entire temperature range under study. In the vicinity of a temperature of 250 ºC in PMN, an abrupt decrease in the coefficient of linear expansion from 1.06∙10-5 K-1 to 0.32∙10-5 K-1, which is possibly associated with a change in the anharmonicity of the potential relief of atoms in the structure, is recorded.

scholarly journals The Transformation of the Structure at Heating and Mechanism of Thermal Expansion of Sn-Bi Eutectic Alloy

2017 ◽  
Vol 18 (2) ◽  
pp. 198-205
Author(s):  
I.I. Shtablavyi ◽  
S.I. Mudry ◽  
U.I. Liudkevych
Keyword(s):  
Thermal Expansion ◽  
Short Range ◽  
Short Range Order ◽  
X Ray Diffraction ◽  
Interatomic Distances ◽  
X Ray ◽  
Temperature Range ◽  
Temperature Dependences ◽  
Order Structures ◽  
Eutectic Melt

The short range order structures of Sn-Bi eutectic melt has been studied by means of X-ray diffraction and reverse Monte-Carlo methods within 420 – 1120 К temperature range. Temperature dependences of interatomic distances and thermal expansion coefficient within first coordination sphere were calculated. Free volume temperature variation was investigated using Voronoi-Delone statistic-geometric method. Obtained data allowed us to find the occurrence of smeared structure transformation in Sn-Bi liquid eutectic and determine the temperature range of this transformation. Results of this study have a potential application in soldering technologies, particularly at improving of interface region properties.  

X-ray diffractometry of AlGaAs/GaAs superlattices and GaAs in the temperature range 5–295 K

1989 ◽  
Vol 22 (4) ◽  
pp. 372-375 ◽  
Author(s):  
G. Clec'h ◽  
G. Calvarin ◽  
P. Auvray ◽  
M. Baudet
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
X Ray ◽  
Lattice Constants ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Gaas Substrates ◽  
Expansion Coefficients ◽  
Tetrahedrally Bonded

The temperature dependence of the lattice constants of Al x Ga1 − x As/GaAs superlattices MBE-grown on (001) oriented GaAs substrates was determined by X-ray diffractometry. The thermal expansion coefficients of these materials become negative at low temperatures, like that of GaAs and other tetrahedrally bonded covalent solids. The temperature dependence of the stress in these structures was also studied; although its value increases as temperature decreases, strain remains elastic down to 5 K.

Temperature dependence of lattice constants of the rare-earth hexaborides EuB6and GdB6

2001 ◽  
Vol 34 (2) ◽  
pp. 208-209 ◽  
Author(s):  
Yasuhiko Takahashi ◽  
Masayoshi Fujimoto ◽  
Masashi Tsuchiko ◽  
Ken-Ichi Ohshima
Keyword(s):  
Rare Earth ◽  
Temperature Dependence ◽  
Linear Thermal Expansion ◽  
X Ray ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Temperature Dependences ◽  
Expansion Coefficients ◽  
Ray Patterns ◽  
The Rare Earth

The temperature dependences of the lattice constants of single crystals of the rare-earth hexaborides EuB6and GdB6were determined by analysing the low-temperature X-ray patterns. The lattice constant decreases monotonously with decreasing temperature. The linear thermal expansion coefficients for the two compounds were also obtained by analysing the temperature dependence of the lattice constants.

The crystal structure and thermal expansion of the CCl4 adduct of Dianin's compound

1990 ◽  
Vol 68 (8) ◽  
pp. 1352-1356 ◽  
Author(s):  
Walter Abriel ◽  
André Du Bois ◽  
Marek Zakrzewski ◽  
Mary Anne White
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Dianin's Compound

The crystal structure of the title compound has been determined by single crystal X-ray diffraction data collected at 293 K, and refined to a final Rw of 0.057. The crystals are rhombohedral, space group [Formula: see text], with a = 27.134(8) Å, c = 10.933(2) Å, and Z = 18. The mole ratio of Dianin's compound (4-p-hydroxyphenyl-2,2,4-trimethylchroman) to CCl4 is 6:1. The guest molecules are disordered. X-ray powder diffraction was carried out in the temperature range from 10 to 300 K. From this, the thermal expansion coefficients for the a- and c-axes and the volume have been determined. Keywords: thermal expansion, crystal structure, clathrate.

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