Ultrasonic Attenuation in Insulators at Room Temperature

1966 ◽  
Vol 37 (4) ◽  
pp. 1542-1548 ◽  
Author(s):  
D. W. Oliver ◽  
G. A. Slack
Keyword(s):  
Room Temperature ◽  
Ultrasonic Attenuation

Pressure dependent ultrasonic properties of hcp hafnium metal

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ramanshu P. Singh ◽  
Shakti Yadav ◽  
Giridhar Mishra ◽  
Devraj Singh
Keyword(s):  
Elastic Constants ◽  
Pressure Range ◽  
Room Temperature ◽  
Ultrasonic Attenuation ◽  
Coupling Constants ◽  
Ultrasonic Properties ◽  
Acoustic Coupling ◽  
Third Order Elastic Constants ◽  
The Stability ◽  
The Given

Abstract The elastic and ultrasonic properties have been evaluated at room temperature between the pressure 0.6 and 10.4 GPa for hexagonal closed packed (hcp) hafnium (Hf) metal. The Lennard-Jones potential model has been used to compute the second and third order elastic constants for Hf. The elastic constants have been utilized to calculate the mechanical constants such as Young’s modulus, bulk modulus, shear modulus, Poisson’s ratio, and Zener anisotropy factor for finding the stability and durability of hcp hafnium metal within the chosen pressure range. The second order elastic constants were also used to compute the ultrasonic velocities along unique axis at different angles for the given pressure range. Further thermophysical properties such as specific heat per unit volume and energy density have been estimated at different pressures. Additionally, ultrasonic Grüneisen parameters and acoustic coupling constants have been found out at room temperature. Finally, the ultrasonic attenuation due to phonon–phonon interaction and thermoelastic mechanisms has been investigated for the chosen hafnium metal. The obtained results have been discussed in correlation with available findings for similar types of hcp metals.

Mechanical and thermophysical properties of actinide monocarbides

2018 ◽  
Vol 32 (21) ◽  
pp. 1850248 ◽  
Author(s):  
Devraj Singh ◽  
Amit Kumar ◽  
Vyoma Bhalla ◽  
Ram Krishna Thakur
Keyword(s):  
Thermophysical Properties ◽  
Room Temperature ◽  
Nearest Neighbor ◽  
Ultrasonic Attenuation ◽  
Thermal Relaxation ◽  
Nonlinearity Parameter ◽  
Micro Hardness ◽  
Temperature Dependent ◽  
Third Order ◽  
Pressure Derivative

This paper describes the mechanical and thermophysical properties of actinide monocarbides AnCs (An=Np and Cm) as a function of temperature and crystallographic direction. The temperature-dependent second- and third-order elastic constant (SOECs and TOECs) have been computed first using Coulomb and Born–Mayer potential up to second nearest neighbor. SOECs have been applied to find out mechanical constant such as bulk modulus, shear modulus, tetragonal modulus, Poisson’s ratio and Zener anisotropy for the prediction of futuristic performance of the NpC and CmC. We also found the value of G/B [Formula: see text] 0.59 for the chosen materials, which indicates that NpC and CmC have brittle nature. The computed elastic constants are further applied directly to indirectly find out the ultrasonic velocity, Grüneisen parameters, pressure derivative, Debye temperature, micro-hardness, Breazeale’s nonlinearity parameter, thermal relaxation time and thermal conductivity. These evaluated parameters were finally used to compute ultrasonic attenuation of the NpC and CmC along [Formula: see text], [Formula: see text] and [Formula: see text] directions at room temperature. The behavior of the obtained results of this investigation has been compared with similar type of materials.

scholarly journals Elastic, Mechanical and Thermophysical properties of Single-Phase Quaternary ScTiZrHf High-Entropy Alloy

2021 ◽  
Vol 22 (4) ◽  
pp. 687-696
Author(s):  
Sachin Rai ◽  
Navin Chaurasiya ◽  
Pramod K. Yadawa
Keyword(s):  
Mechanical Properties ◽  
Elastic Constants ◽  
Room Temperature ◽  
Single Phase ◽  
Mechanical Characterization ◽  
Ultrasonic Attenuation ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Different Temperatures ◽  
Ultrasonic Parameters

Consequent to the interaction potential model, the high-order elastic constants at high entropy alloys in single-phase quaternary ScTiZrHf have been calculated at different temperatures. Elastic constants of second order (SOECs) helps to determine other ultrasonic parameters. With the help of SOECs other elastic moduli, bulk modulus, shear modulus, Young’s modulus, Pugh’s ratio, elastic stiffness constants and Poisson’s ratio are estimated at room temperature for elastic and mechanical characterization. The other ultrasonic parameters are calculated at room temperature for elastic and mechanical characterization. The temperature variation of ultrasonic velocities along the crystal's z-axis is evaluated using SOECs. The temperature variation of the  average debye velocity and the thermal relaxation time (τ) are also estimated along this orientation axis. The ultrasonic properties correlated with elastic, thermal and mechanical properties which is temperature dependent is also discussed. The ultrasonic attenuation due to phonon – phonon (p-p) interactions is also calculated at different temperatures. In the study of ultrasonic attenuation such as a function of temperature, thermal conductivity appears to be main contributor and p- p interactions are the responsible reason of attenuation and found that the mechanical properties of the high entropy alloy ScTiZrHf are superior at room temperature.

Low frequency damping and ultrasonic attenuation in Ti3Sn-based alloys

1994 ◽  
Vol 9 (6) ◽  
pp. 1441-1448 ◽  
Author(s):  
Catherine R. Wong ◽  
Robert L. Fleischer
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Ultrasonic Attenuation ◽  
Low Frequency ◽  
Basic Mechanism ◽  
Low Frequencies ◽  
High Frequencies ◽  
Young’S Moduli ◽  
High Temperature Alloys ◽  
Damping Behavior

Studies of high-temperature alloys in the Ti-Sn system based on the intermetallic compound Ti3Sn have identified alloys that damp strongly both at low frequencies (0.1 to 10 Hz) and high frequencies (5 to 20 MHz). The low frequency damping behavior shows loss factors as high as 0.04 at room temperature and Young's moduli that rise with temperature from 40 °C to 100 °C for two alloys. Although the basic mechanism or mechanisms of energy dissipation are presently unknown, the alloys are notable for unusual shapes of microhardness indentations. The deformations imply that large reversible strains can occur at temperatures from 23 °C to 1150 °C.

ELASTIC AND ACOUSTIC PROPERTIES OF HEXAGONALCr2NbCOMPOUND

2014 ◽  
Vol 02 (03n04) ◽  
pp. 1450001
Author(s):  
PRAMOD KUMAR YADAWA
Keyword(s):  
Sound Velocity ◽  
Room Temperature ◽  
Ultrasonic Attenuation ◽  
Acoustic Properties ◽  
Third Order ◽  
Jones Potential ◽  
Ultrasonic Properties ◽  
Third Order Elastic Constants ◽  
Ultrasonic Sound ◽  
Thermal And Electrical Properties

The ultrasonic properties like ultrasonic sound velocity in the hexagonal structured Cr2Nb compound have been studied along unique axis at room temperature. The second- and third-order elastic constants (SOECs and TOECs) have been calculated for this compound using Lennard–Jones potential. The velocities VLand VS1have minima and maxima respectively with 45° with unique axis of the crystal, while VS2increases with the angle from unique axis. Debye average sound velocities of Cr2Nb have been found to be increasing with the angle and has maximum at 55° with unique axis at room temperature. Hence, when a sound wave travels at 55° with unique axis of this material, then the average sound velocity is found to be maximum. The inconsistent behavior of angle dependent velocities is associated to the action of SOECs. The ultrasonic properties are discussed in correlation with elastic, thermal and electrical properties. It has been found that the thermal conductivity is the main contributor to the behavior of ultrasonic attenuation and the cause of attenuation is phonon–phonon interaction. The mechanical properties of Cr2Nb are better than other chromium-based alloys ( Cr2Ta , Cr2Zr and Cr2Hf ) at room temperature, because it has high ultrasonic velocity and low ultrasonic attenuation.

scholarly journals Computations of Ultrasonic Parameters in Alloys

2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
Pramod Kumar Yadawa
Keyword(s):  
Sound Velocity ◽  
Elastic Constants ◽  
Room Temperature ◽  
Ultrasonic Attenuation ◽  
Physical Parameters ◽  
Third Order ◽  
Ultrasonic Properties ◽  
Third Order Elastic Constants ◽  
Ultrasonic Parameters

The ultrasonic properties like ultrasonic attenuation, sound velocity in the hexagonal alloys have been studied along unique axis at room temperature. The second- and third-order elastic constants (SOEC & TOEC) have been calculated for these alloys using Lennard-Jones potential. The velocities and have minima and maxima, respectively, at 45° with unique axis of the crystal, while increases with the angle from unique axis. The inconsistent behaviour of angle-dependent velocities is associated to the action of second-order elastic constants. Debye average sound velocities of these alloys are increasing with the angle and has maximum at 55° with unique axis at room temperature. Hence, when a sound wave travels at 55° with unique axis of these alloys, then the average sound velocity is found to be maximum. The mechanical and ultrasonic properties of these alloys will be better than pure Zr and Sn due to their high SOEC and ultrasonic velocity and low ultrasonic attenuation. The comparison of calculated ultrasonic parameters with available theoretical/experimental physical parameters gives information about classification of these alloys.

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