Effects of Heating Atmosphere on Structure and Thermal Expansion of Aluminum Alloys

2015 ◽  
Vol 788 ◽  
pp. 163-169 ◽  
Author(s):  
Vladimir Afanasyef ◽  
Marina Popova ◽  
Aleksandr Prudnikov
Keyword(s):  
Solid Solution ◽  
Thermal Expansion ◽  
Aluminum Alloys ◽  
Hydrogen Content ◽  
Linear Expansion ◽  
Linear Thermal Expansion ◽  
High Oxygen Content ◽  
Temperature Range ◽  
Oxidizing Atmosphere ◽  
Coefficient Of Linear Expansion

This paper analyses effects of boiling treatment of aluminum alloys (Al–(5-10)% Cu and Al–(5-10)% Si) in oxidizing atmosphere on their microstructure, hydrogen content and coefficient of linear thermal expansion (CLE). Boiling treatment was conducted in water solutions of KMnO4and KOH. Following an increase of boiling time from 15 to 75 hours hydrogen content in alloys first increases and then decreases which correlates with the dynamics of alloys’ microstructure and their coefficient of linear expansion. This study shows that atmosphere with high oxygen content induces acceleration of diffusion processes in aluminum alloys. If boiling time does not exceed 30 hours, hydrogen content in solid solution and etchability of grain boundaries of α-solid solution decrease and intermediate phases get partially dissolved. In our empirical study we demonstrated that boiling treatment of aluminum alloys in oxidizing atmosphere in the range of test temperatures 50-450°С leads to a reduction of the coefficient of linear expansion. The decrease of the coefficient of linear expansion is especially strong in the temperature range of 250-350°С. In particular, after boiling treatment of alloys Al–(5-10)% Cu in oxidizing athmosphere in the temperature range of 50–250°С their coefficient of linear expansion goes down by 10-12%. For alloys Al–(5-10)% Si boiling has a stronger effect on the coefficient of linear expansion – in the temperature range 250-350°С the CLE of these alloys decreases by 24-28%.

scholarly journals Thermal Expansion and Electro-Elastic Features of Ba2TiSi2O8 High Temperature Piezoelectric Crystal

Crystals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 11 ◽  
Author(s):  
Chao Jiang ◽  
Feifei Chen ◽  
Fapeng Yu ◽  
Shiwei Tian ◽  
Xiufeng Cheng ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Elastic Properties ◽  
Piezoelectric Coefficient ◽  
Linear Thermal Expansion ◽  
Temperature Stability ◽  
Promising Candidate ◽  
Temperature Range ◽  
Sensor Applications ◽  
High Temperature Sensor

A high-quality Ba2TiSi2O8 (BTS) single crystal was grown using the Czochralski (Cz) pulling method. The thermal expansion and electro-elastic properties of BTS crystal were studied for high temperature sensor applications. The relative dielectric permittivities ε 11 T / ε 0 and ε 33 T / ε 0 were determined to be 16.3 and 11.8, while the piezoelectric coefficients d15, d31, d33 were found to be 17.8, 2.9, and 4.0 pC/N, respectively. Temperature dependence of electro-elastic properties were investigated, where the variation of elastic compliance s 55 E (= s 44 E ) was found to be <6% over temperature range of 20–700 °C. Taking advantage of the anisotropic thermal expansion, linear thermal expansion comparable to insulating alumina ceramic was achieved over temperature range up to 650 °C. The optimum crystal cut with large effective piezoelectric coefficient (>8.5 pC/N) and linear thermal expansion coefficient (8.03 ppm/°C) achieved for BTS crystal along the (47°, φ) direction (φ is arbitrary in 0–360°), together with its good temperature stability up to 650 °C, make BTS crystal a promising candidate for high temperature piezoelectric sensors.

Linear Thermal Expansion of Lead-Free Piezoelectric K0.5Na0.5NbO3 Ceramics in a Wide Temperature Range

2011 ◽  
Vol 94 (8) ◽  
pp. 2273-2275 ◽  
Author(s):  
Barbara Malič ◽  
Helena Razpotnik ◽  
Jurij Koruza ◽  
Samo Kokalj ◽  
Jena Cilenšek ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Wide Temperature Range ◽  
Linear Thermal Expansion ◽  
Lead Free ◽  
Temperature Range

Combustion Synthesis of ZrW2O8 and Preparation of its Composite with Near Zero Thermal Expansion

2007 ◽  
Vol 353-358 ◽  
pp. 1235-1238 ◽  
Author(s):  
Xue Yan ◽  
Xiao Nong Cheng ◽  
Xin Bo Yang ◽  
Cheng Hua Zhang
Keyword(s):  
Thermal Expansion ◽  
Combustion Synthesis ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Linear Thermal Expansion Coefficient ◽  
Linear Thermal Expansion ◽  
Weight Ratio ◽  
Combustion Method ◽  
Temperature Range ◽  
Thermal Expansion Property

ZrW2O8 was successfully synthesized via combustion method with (NH4)5H5[H2(WO4)6] ·H2O, ZrOCl2·8H2O, H3BO3, (NH2)2CO and HNO3. The best prescription of combustion synthesizing of ZrW2O8 was obtained. The linear thermal expansion coefficient of synthesized ZrW2O8 is -5.08×10-6oC-1 in the temperature range of 50-600oC. Different weight ratios of ZrW2O8 and ZrO2 were taken into account. Al2O3 was added into the composite during sintering to increase the density of the composites. When the weight ratio of ZrO2 to ZrW2O8 is 2, the composite with near zero thermal expansion can be obtained. 0.25 wt% Al2O3 can effectively increase the density of ZrO2/ZrW2O8 composites with slight influence on the thermal expansion property.

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.

THERMO-MECHANICAL ANALYSIS OF HETEROGENEOUS SOLID ROCKET PROPELLANT

2019 ◽  
Vol 147 (3/2018) ◽  
pp. 105-121
Author(s):  
Marcin Cegla ◽  
Janusz Zmywaczyk ◽  
Piotr Koniorczyk
Keyword(s):  
Thermal Expansion ◽  
Loss Modulus ◽  
Linear Thermal Expansion ◽  
Softening Temperature ◽  
Mechanical Analysis ◽  
Solid Rocket Propellant ◽  
Rocket Propellant ◽  
Temperature Range ◽  
Solid Rocket ◽  
Heterogeneous Solid

The article presents results of thermo-mechanical analysis of heterogeneous solid rocket propellant H2, with special attention devoted to determining the glass transition temperature and softening temperature. Mechanical properties such as storage modulus (E’), loss modulus (E’’) and tan(δ) were measured using NETZSCH DMA 242C analyzer within temperature range from -120oC to +80oC at 2 K/min of heating rate and frequency of applied force f = 1 Hz. Relative thermal expansion as well as the Coefficient of Linear Thermal Expansion (CLTE) of H2 sample were determined using NETZSCH DIL 402C dilatometer within temperature range from 30oC to 80oC at 1 K/min of heating/cooling rate. The thermophysical properties including thermal conductivity, thermal diffusivity, and specific heat were determined within temperature range from -20oC to +80oC using KD2 Pro apparatus.

Negative Thermal Expansion of Yb2Mo3O12 and Lu2Mo3O12

2008 ◽  
Vol 368-372 ◽  
pp. 1662-1664 ◽  
Author(s):  
X.L. Xiao ◽  
M.M. Wu ◽  
J. Peng ◽  
Y.Z. Cheng ◽  
Zhong Bo Hu
Keyword(s):  
Thermal Expansion ◽  
Solid State ◽  
Solid State Reaction ◽  
Linear Thermal Expansion ◽  
Negative Thermal Expansion ◽  
Orthorhombic Structure ◽  
Conventional Solid State Reaction ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

Compounds Yb2Mo3O12 and Lu2Mo3O12 were prepared by conventional solid-state reaction. Their crystal structures and thermal expansion properties were investigated. It was found that Yb2Mo3O12 and Lu2Mo3O12 adopt orthorhombic structure and show negative thermal expansion (NTE) in the temperature range of 200-800 °C. Their a-axis and c-axis exhibit stronger contraction in the temperature range of 200-800 °C, while b-axis slightly expands in the temperature range of 200-300 °C and then contracts in the temperature range of 300-800 °C. The linear thermal expansion coefficients al of Yb2Mo3O12 and Lu2Mo3O12 are −5.17 × 10−6 °C−1 and −5.67 × 10−6 °C−1, respectively.

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.

Dilatometric Investigation of the Phase Transformations in ChS-139 Steel

2013 ◽  
Vol 8 (3) ◽  
pp. 159-162
Author(s):  
Yuriy Kozlovskii ◽  
Sergey Stankus ◽  
Rashid Khairulin ◽  
Oleg Yatsuk
Keyword(s):  
Thermal Expansion ◽  
Phase Transformations ◽  
Linear Thermal Expansion ◽  
Temperature Range ◽  
Relative Expansion ◽  
Temperature Dependences ◽  
Dilatometric Investigation

The results of the dilatometric investigation of the phase transformations in ChS-139 steel over the temperature range from 20 to 1 000С are presented. The error in the coefficient of linear thermal expansion (TCLE) is (1.5–2)  10–7 К–1. The temperatures of the phase transformations, the changes of relative expansion on mutual austenite-martensite transitions, and TCLE of all phases are determined. An interpretation of a number of specific points in the temperature dependences of the properties is given

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