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.

Ultrasonic Investigations on Polonides of Ba, Ca, and Pb

2017 ◽  
Vol 72 (11) ◽  
pp. 977-983 ◽  
Author(s):  
Devraj Singh ◽  
Vyoma Bhalla ◽  
Jyoti Bala ◽  
Shikha Wadhwa
Keyword(s):  
Room Temperature ◽  
Ultrasonic Attenuation ◽  
Thermal Relaxation ◽  
Theoretical Data ◽  
Coupling Constants ◽  
Temperature Dependent ◽  
Phonon Interaction ◽  
Third Order ◽  
Acoustic Coupling ◽  
Third Order Elastic Constants

AbstractThe temperature-dependent mechanical and ultrasonic properties of barium, calcium, and lead polonides (BaPo, CaPo, and PbPo) were investigated in the temperature range 100–300 K. The second- and third-order elastic constants (SOECs and TOECs) were computed using Coulomb and Born-Mayer potential and these in turn have been used to estimate other secondary elastic properties such as strength, anisotropy, microhardness, etc. The theoretical approach followed the prediction that BaPo, CaPo, and PbPo are brittle in nature. PbPo is found to be the hardest amongst the chosen compounds. Further the SOECs and TOECs are applied to determine ultrasonic velocities, Debye temperature, and acoustic coupling constants along <100>, <110>, and <111> orientations at room temperature. Additionally thermal conductivity has been computed using Morelli and Slack’s approach along different crystallographic directions at room temperature. Finally ultrasonic attenuation due to phonon–phonon interaction and thermoelastic relaxation mechanisms has been computed for BaPo, CaPo, and PbPo. The behaviour of these compounds is similar to that of semi-metals with thermal relaxation time of the order 10−11 s. The present computation study is reasonably in agreement with the available theoretical data for the similar type of materials.

Behaviour of elastic and ultrasonic properties of curium monopnictides

2018 ◽  
Vol 96 (5) ◽  
pp. 513-518 ◽  
Author(s):  
Chinmayee Tripathy ◽  
Devraj Singh ◽  
Rita Paikaray
Keyword(s):  
Elastic Constants ◽  
Ultrasonic Attenuation ◽  
Thermal Relaxation ◽  
Coupling Constant ◽  
Temperature Dependent ◽  
Third Order ◽  
Ultrasonic Properties ◽  
Acoustic Coupling ◽  
Anisotropic Factor ◽  
Third Order Elastic Constants

The temperature-dependent elastic and ultrasonic properties of curium monopnictides CmPn (Pn = N, P, As, Sb) have been explored in the present investigation. The second- and third-order elastic constants have been calculated using Coulomb and Born–Mayer potentials using lattice and hardness parameters. Mechanical parameters, such as Young’s modulus, bulk modulus, shear modulus, tetragonal modulus, anisotropic factor, and Poisson’s ratio, have been computed with second-order elastic constants. These materials fulfilled the requirement of the Born stability criterion. The toughness or fracture ratio is found to be more than 0.57 in CmPn, which indicates their brittle nature. In addition, the ultrasonic wave velocity, Debye average velocity, Debye temperature, thermal relaxation time, thermal conductivity, acoustic coupling constant, and ultrasonic attenuation have also been computed along ⟨100⟩, ⟨110⟩, ⟨111⟩ directions at room temperature. The results are discussed in correlation with other similar types of the materials.

Investigation of zirconium nanowire by elastic, thermal and ultrasonic analysis

2020 ◽  
Vol 75 (12) ◽  
pp. 1077-1084
Author(s):  
Bhawan Jyoti ◽  
Shakti Pratap Singh ◽  
Mohit Gupta ◽  
Sudhanshu Tripathi ◽  
Devraj Singh ◽  
...  
Keyword(s):  
Ultrasonic Attenuation ◽  
Thermal Relaxation ◽  
Coupling Constants ◽  
Physical Parameters ◽  
Third Order ◽  
Jones Potential ◽  
Acoustic Coupling ◽  
Anisotropic Factor ◽  
Third Order Elastic Constants ◽  
Ultrasonic Analysis

AbstractThe elastic, thermal and ultrasonic properties of zirconium nanowire (Zr-NW) have been investigated at room temperature. The second and third order elastic constants (SOECs and TOECs) of Zr-NW have been figured out using the Lennard–Jones Potential model. SOECs have been used to find out the Young’s modulus, bulk modulus, shear modulus, Poisson’s ratio, Pugh’s ratio, Zener anisotropic factor and ultrasonic velocities. Further these associated parameters of Zr-NW have been utilized for the evaluation of the Grüneisen parameters, thermal conductivity, thermal relaxation time, acoustic coupling constants and ultrasonic attenuation. On the basis of the above analyzed properties of Zr-NW, some characteristics features of the chosen nanowire connected with ultrasonic and thermo-physical parameters have been discussed.

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.

scholarly journals Effect of Microstructure on Thermophysical Properties of Heat-Treated Duplex Steel

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6043
Author(s):  
Piotr Koniorczyk ◽  
Judyta Sienkiewicz ◽  
Janusz Zmywaczyk ◽  
Andrzej Dębski ◽  
Mateusz Zieliński ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Laser Flash ◽  
Micro Hardness ◽  
Scanning Calorimetry ◽  
Air Atmosphere ◽  
Steel Bar ◽  
Heat Treated ◽  
Duplex Steel

The purpose of this study is to investigate the effect of heat treatments and resulting changes in microstructure on the thermophysical properties of commercial 1.4462 duplex stainless steel. Three types of heat treatment and a raw sample were used. In the first heat treatment, a duplex steel bar was annealed in an air atmosphere furnace for one hour at 1200 °C and then quickly cooled in water (1200 °C + water). The second heat treatment was the same as the first, but afterwards, the bar was annealed in an air atmosphere furnace for 4 h at 800 °C and then slowly cooled down in the furnace to room temperature (1200 °C + water + 800 °C). In the third heat treatment, the duplex steel bar was annealed in the furnace in an air atmosphere for one hour at 900 °C and then slowly cooled in the furnace to room temperature (900 °C). As a result, the weight percentages of ferrite and austenite in the samples achieved the following ratios: 75:25, 65:35 and 44:56. Light microscope examinations (LM), scanning electron microscopy (SEM), Vickers micro-hardness measurements and thermophysical studies using a laser flash apparatus (LFA), differential scanning calorimetry (DSC) and push-rod dilatometry (DIL) were performed to reveal the microstructure and changes in thermophysical properties including thermal diffusivity, thermal conductivity, thermal expansion and specific heat. Along with presenting these data, the paper, in brief, presents the applied investigation procedures.

MECHANICAL AND THERMAL PROPERTIES OF PRASEODYMIUM MONOPNICTIDES: AN ULTRASONIC STUDY

2013 ◽  
Vol 27 (22) ◽  
pp. 1350116 ◽  
Author(s):  
VYOMA BHALLA ◽  
RAJ KUMAR ◽  
CHINMAYEE TRIPATHY ◽  
DEVRAJ SINGH
Keyword(s):  
Elastic Constants ◽  
Room Temperature ◽  
Ultrasonic Attenuation ◽  
Poisson Ratio ◽  
Higher Order ◽  
Coupling Constants ◽  
Nonlinearity Parameter ◽  
Mechanical And Thermal Properties ◽  
Temperature Range ◽  
G Ratio

We have computed ultrasonic attenuation, acoustic coupling constants and ultrasonic velocities of praseodymium monopnictides PrX ( X : N , P , As , Sb and Bi ) along the 〈100〉, 〈110〉, 〈111〉 in the temperature range 100–500 K using higher order elastic constants. The higher order elastic constants are evaluated using Coulomb and Born–Mayer potential with two basic parameters viz. nearest-neighbor distance and hardness parameter in the temperature range of 0–500 K. Several other mechanical and thermal parameters like bulk modulus, shear modulus, Young's modulus, Poisson ratio, anisotropic ratio, tetragonal moduli, Breazeale's nonlinearity parameter and Debye temperature are also calculated. In the present study, the fracture/toughness (B/G) ratio is less than 1.75 which implies that PrX compounds are brittle in nature at room temperature. The chosen material fulfilled Born criterion of mechanical stability. We also found the deviation of Cauchy's relation at higher temperatures. PrN is most stable material as it has highest valued higher order elastic constants as well as the ultrasonic velocity. Further, the lattice thermal conductivity using modified approach of Slack and Berman is determined at room temperature. The ultrasonic attenuation due to phonon–phonon interaction and thermoelastic relaxation mechanisms have been computed using modified Mason's approach. The results with other well-known physical properties are useful for industrial applications.

Size-Dependent Ultrasonic and Thermophysical Properties of Indium Phosphide Nanowires

2020 ◽  
Vol 75 (4) ◽  
pp. 373-380 ◽  
Author(s):  
Sudhanshu Tripathi ◽  
Rekha Agarwal ◽  
Devraj Singh
Keyword(s):  
Indium Phosphide ◽  
Thermophysical Properties ◽  
Elastic Anisotropy ◽  
Ultrasonic Attenuation ◽  
Third Order ◽  
Size Dependent ◽  
Third Order Elastic Constants ◽  
Ultrasonic Characterization ◽  
Nearest Neighbours ◽  
Non Destructive

AbstractThe present work explores the diameter- and temperature-dependent ultrasonic characterization of wurtzite indium phosphide nanowires (WZ-InP-NWs) using a theoretical model based on the ultrasonic non-destructive evaluation (NDE) technique. Initially, the second- and third-order elastic constants (SOECs and TOECs) were computed using the Lennard-Jones potential model, considering the interactions up to the second nearest neighbours. Simultaneously, the mechanical parameters (Young’s modulus, shear modulus, elastic anisotropy factor, bulk modulus, Pugh’s ratio and Poisson’s ratio) were also estimated. Finally, the thermophysical properties and ultrasonic parameters (velocity and attenuation) of the InP-NWs were determined using the computed quantities. The obtained elastic/mechnical properties of the InP-NWs were also analyzed to explore the mechanical behaviors. The correlations between temperature-/size-dependent ultrasonic attenuation and the thermophysical properties were established. The ultrasonic attenuation was observed to be the third-order polynomial function of the diameter/temperature for the InP nanowire.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

Temperature Dependent Line-Shape of the Silicon Dangling Bond EPR-Resonance in Polycrystalline Silicon

1996 ◽  
Vol 452 ◽  
Author(s):  
N. H. Nickel ◽  
E. A. Schiff
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Polycrystalline Silicon ◽  
Room Temperature ◽  
Dangling Bond ◽  
Temperature Dependent ◽  
Paramagnetic Resonance ◽  
Temperature Electron ◽  
Motional Narrowing ◽  
G Value ◽  
Electron Paramagnetic

AbstractThe temperature dependence of the silicon dangling-bond resonance in polycrystalline (poly-Si) and amorphous silicon (a-Si:H) was measured. At room temperature, electron paramagnetic resonance (EPR) measurements reveal an isotropie g-value of 2.0055 and a line width of 6.5 and 6.1 G for Si dangling-bonds in a-Si:H and poly-Si, respectively. In both materials spin density and g-value are independent of temperature. While in a-Si:H the width of the resonance did not change with temperature, poly-Si exhibits a remarkable T dependence of ΔHpp. In unpassivated poly-Si a pronounced decrease of ΔHpp is observed for temperatures above 300 K. At 384 K ΔHpp reaches a minimum of 5.1 G, then increases to 6.1 G at 460 K, and eventually decreases to 4.6 G at 530 K. In hydrogenated poly-Si ΔHpp decreases monotonically above 425 K. The decrease of ΔHpp is attributed to electron hopping causing motional narrowing. An average hopping distance of 15 and 17.5 Å was estimated for unhydrogenated and H passivated poly-Si, respectively.

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