High Temperature Elastic Properties of Refractory Materials

2011 ◽  
Vol 673 ◽  
pp. 59-64
Author(s):  
Mahdi Ghassemi Kakroudi ◽  
Shahin Khameneh Asl

A pulse-echo technique, based on ultrasonic "long-bar" mode (LBM) velocity measurements, working up to 1700°C is described. Magnetostrictive transducers and ultrasonic lines used in a 40-350 kHz frequency range are detailed. The conditions of choice of fundamental parameters (frequency, line geometry, sample size) are discussed in relation with the nature and the microstructure of the materials under test. This technique can be used to study the variations of elastic moduli of materials at high temperature.

2015 ◽  
Vol 770 ◽  
pp. 179-184
Author(s):  
Elena P. Tesleva

The article studies the elastic properties of anisotropy and interatomic anharmonicity in a two-component Cu3Au alloy with positional order-disorder within the high temperature interval of 300 К and 725 К. It provides calculations on velocities of purely transverse and longitudinal elastic waves, elastic moduli (Young’s, shear, adiabatic bulk moduli) and Poisson’s ratios based on the stiffness constants сij(T) of the crystal. Sound velocity values were employed for determining the temperature changes of Grüneisen parameter along the crystallographic directions [100], [110] and [111].


2020 ◽  
Vol 307 ◽  
pp. 321-326
Author(s):  
Nurhayati Mohd Nor ◽  
Halimah Mohamed Kamari ◽  
Amirah Abdul Latif ◽  
Nurisya Mohd Shah

Silica borotellurite glasses doped with different molar fraction of V2O5 have been prepared by melt quenching technique. The elastic properties of {[(TeO2)0.7 (B2O3)0.3]0.8(SiO2)0.2}(1-x)(V2O5)x glasses are investigated using ultrasonic pulse echo measurements and their elastic properties have been characterized at room temperature. The density of the glasses was measured by Archimedes method using distilled water as buoyant liquid. The ultrasonic wave velocities (longitudinal, vl and shear, vS) were recorded at 5 MHz. Elastic moduli, Poisson’s ratio (σ) and microhardness (H) were then calculated to obtain quantitative analysis regarding the structure of these glasses. The results obtained showed that the doping of V2O5 with silica borotellurite enhances the strengthening of glass network. Glass with 0.03 molar fraction of V205 shows low ultrasonic velocities and low elastic moduli. The variation of elastic properties is related to the change of structure in the vanadium doped silica-borotellurite glass system.


Author(s):  
Bianca Reis Moya ◽  
Idalci Cruvinel dos Reis ◽  
Victor Ciro Solano Reynoso ◽  
Mariana da Silva Barros ◽  
Kamila Ruthielle Silva Gomes

ABSTRACT: The PbO-SrO-B2O3 glass system with the of molar ratio of R (= PbO/B2O3) were prepared by fusion method. The elastic properties have been investigated using longitudinal and transversal ultrasonic wave velocity. Measurements were performed at room temperature and using pulse-echo technique at frequency of 5 MHz. The results indicate that, when increasing R value, the glass network stability decreases. This decrease indicates, of the increase the number of borate structures with non bridging oxygen (NBOs) at the expense of the decrease of borate units with tetrahedral structures. This feature may lead to the more open glass network structures and lower stiffness of the samples studied.


2005 ◽  
Vol 20 (3) ◽  
pp. 719-725 ◽  
Author(s):  
Ori Yeheskel ◽  
Rachman Chaim ◽  
Zhijian Shen ◽  
Mats Nygren

Dense MgO ceramics with nanometer to submicrometer grain size were fabricated by high-temperature hot-isostatic pressing, low-temperature hot-pressing, and spark plasma sintering. The elastic properties were determined by sound wave velocity measurements. Young's and shear moduli of nanocrystalline MgO were lower by 13% than those with submicrometer grain size. Softening of the elastic properties was analyzed and related to the lower density and lower elastic moduli of the grain boundaries compared to the crystal interior. Young's and shear moduli of the grain boundaries were evaluated as 90 and 34 GPa, respectively. This leads to a more than 3-fold decrease in the effective elastic moduli with the decrease of grain size into the nanometer range.


2012 ◽  
Vol 2 (5) ◽  
pp. 546-548
Author(s):  
P. Vasantharani P. Vasantharani ◽  
◽  
I.Sankeeda I.Sankeeda

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 968
Author(s):  
Fumitada Iguchi ◽  
Keisuke Hinata

The elastic properties of 0, 10, 15, and 20 mol% yttrium-doped barium zirconate (BZY0, BZY10, BZY15, and BZY20) at the operating temperatures of protonic ceramic fuel cells were evaluated. The proposed measurement method for low sinterability materials could accurately determine the sonic velocities of small-pellet-type samples, and the elastic properties were determined based on these velocities. The Young’s modulus of BZY10, BZY15, and BZY20 was 224, 218, and 209 GPa at 20 °C, respectively, and the values decreased as the yttrium concentration increased. At high temperatures (>20 °C), as the temperature increased, the Young’s and shear moduli decreased, whereas the bulk modulus and Poisson’s ratio increased. The Young’s and shear moduli varied nonlinearly with the temperature: The values decreased rapidly from 100 to 300 °C and gradually at temperatures beyond 400 °C. The Young’s modulus of BZY10, BZY15, and BZY20 was 137, 159, and 122 GPa at 500 °C, respectively, 30–40% smaller than the values at 20 °C. The influence of the temperature was larger than that of the change in the yttrium concentration.


Author(s):  
M. A. Hassan ◽  
Manabendra Pathak ◽  
Mohd. Kaleem Khan

The temperature and concentration play an important role on rheological parameters of the gel. In this work, an experimental investigation of thermorheological properties of aqueous gel Carbopol Ultrez 20 for various concentrations and temperatures has been presented. Both controlled stress ramps and controlled stress oscillatory sweeps were performed for obtaining the rheological data to find out the effect of temperature and concentration. The hysteresis or thixotropic seemed to have negligible effect. Yield stress, consistency factor, and power law index were found to vary with temperature as well as concentration. With gel concentration, the elastic effect was found to increase whereas viscous dissipation effect was found to decrease. Further, the change in elastic properties was insignificant with temperature in higher frequency range of oscillatory stress sweeps.


2018 ◽  
Vol 103 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Takanori Sakairi ◽  
Tatsuya Sakamaki ◽  
Eiji Ohtani ◽  
Hiroshi Fukui ◽  
Seiji Kamada ◽  
...  

Open Physics ◽  
2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Lili Liu ◽  
Xiaozhi Wu ◽  
Weiguo Li ◽  
Rui Wang ◽  
Qing Liu

AbstractThe high temperature and pressure effects on the elastic properties of the AgRE (RE=Sc, Tm, Er, Dy, Tb) intermetallic compounds with B2 structure have been performed from first principle calculations. For the temperature range 0-1000 K, the second order elastic constants for all the AgRE intermetallic compounds follow a normal behavior: they decrease with increasing temperature. The pressure dependence of the second order elastic constants has been investigated on the basis of the third order elastic constants. Temperature and pressure dependent elastic anisotropic parameters A have been calculated based on the temperature and pressure dependent elastic constants.


2006 ◽  
Vol 74 (18) ◽  
Author(s):  
O. Svitelskiy ◽  
A. Suslov ◽  
D. L. Schlagel ◽  
T. A. Lograsso ◽  
K. A. Gschneidner ◽  
...  

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