Lattice Thermal Expansion of Praseodymium and Neodymium

1984 ◽  
pp. 49-57
Author(s):  
J. V. S. S. Narayana Murty ◽  
R. Ramji Rao ◽  
A. Ramanand
Keyword(s):  
Thermal Expansion ◽  
Lattice Thermal Expansion

Lattice thermal expansion of CsPbBr3 in the cubic phase

1986 ◽  
Vol 5 (12) ◽  
pp. 1324-1324
Author(s):  
J. Sadanandam ◽  
S. V. Suryanarayana
Keyword(s):  
Thermal Expansion ◽  
Cubic Phase ◽  
Lattice Thermal Expansion

Lattice Thermal Expansion of the Shape Memory Alloys Cu-Al-Ni, Cu-Al-Zn, Cu-Al-Be and Cu-Al-Pd

2008 ◽  
Vol 52 ◽  
pp. 135-142
Author(s):  
Santhosh Potharay Kuruvilla ◽  
C.S. Menon
Keyword(s):  
Thermal Expansion ◽  
Shape Memory ◽  
Wave Velocity ◽  
Elastic Constants ◽  
Damping Capacity ◽  
Shear Mode ◽  
Potential Candidate ◽  
Lattice Thermal Expansion ◽  
Third Order ◽  
Third Order Elastic Constants

Theoretical and experimental investigations are being carried out on Cu based alloys due to their technologically important shape memory properties and pseudo-elasticity, which are intimately associated with the martensitic transformation. The transition between the two phases, martensite to austenite, is of continued interest in academics and in industry. The shape memory effect, superelastic properties and biocompatibility are being applied in a variety of fields. Cu based SMA system has large vibrational entropy, high damping capacity and good economic viability. All these make it a potential candidate in the field of sensors and actuators. The concurrent knowledge of the second order elastic constants (SOEC) and third order elastic constants (TOEC) enables a better understanding of the nonlinear elasticity exhibited by these alloys. We have used a model based on deformation theory and Keating’s potential scheme to obtain the expressions for TOEC of the above alloys. In this paper we have calculated the complete sets of six non-vanishing TOEC of Cu-Al-Ni, Cu-Al-Zn, Cu-Al-Be and Cu-Al-Pd and are presented along with the available experimental data. It is remarkable that all the third order elastic constants are negative, indicating an increase in the vibrational frequencies under stress, giving rise to an increase in the strain-free energy. The absolute values of the TOEC are large. This means that the bcc phase observed is considerably anharmonic. The TOEC C144 representing the shear mode has a smaller value than C111. Hence, the effect of pressure is much greater on longitudinal wave velocity than on the shear wave velocity in the above Cu based SMA. The mode Grüneisen parameters of the acoustic waves are determined based on the quasi-harmonic approximation method. The low temperature limit of the lattice thermal expansion and the Anderson– Grüneisen parameter of these alloys are also obtained.

Models for lattice thermal expansion and thermal conductivity for ternary (ANB2+NC27−N) tetrahedral semiconductors

2011 ◽  
Vol 127 (1-2) ◽  
pp. 74-78 ◽  
Author(s):  
Ajay Singh Verma ◽  
Bimal Kumar Sarkar ◽  
Sheetal Sharma ◽  
Rajiv Bhandari ◽  
Vijay Kumar Jindal
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Lattice Thermal Expansion ◽  
Tetrahedral Semiconductors

High Temperature Guinier X-Ray Diffractometry for Thermal Expansion Measurements in the Hexagonal form of Cordierite ((2MgO•2Al2O3•5SiO2)

1983 ◽  
Vol 27 ◽  
pp. 397-404
Author(s):  
J. S. Pressnall ◽  
J. J. Fitzpatrick ◽  
Paul Predecki
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Close Agreement ◽  
Accurate Determination ◽  
Critical Test ◽  
Lattice Thermal Expansion ◽  
X Ray ◽  
Hexagonal Form ◽  
Computer Controlled

AbstractA computer-controlled high temperature Guinier diffractometer system for accurate determination of lattice thermal expansion is described. A critical test of the system using α-Al2O3 (0.3μ polishing alumina) showed close agreement with the single crystal expansion data of Wachtman et al. Lattice thermal expansion of cordierite doped with the following dopants: Ge+4, P+5, Zn+2, Li+1 and Ca+2 was investigated. Of these the Li+1 at the 5% level (5% of Si+4 replaced by Li+1 + Al+3) produced the largest decrease in mean lattice expansion.

Lattice thermal expansion of Pu1−yAmyO2−xplutonium–americium mixed oxides

2017 ◽  
Vol 50 (6) ◽  
pp. 1782-1790 ◽  
Author(s):  
Romain Vauchy ◽  
Alexis Joly ◽  
Christophe Valot
Keyword(s):  
Thermal Expansion ◽  
Elevated Temperatures ◽  
Mixed Oxides ◽  
Lattice Parameter ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Lattice Thermal Expansion ◽  
Linear Lattice ◽  
The Face

Plutonium–americium mixed oxides, Pu1−yAmyO2−x, with various Am contents (y= 0.018, 0.077, 0.21, 0.49, 0.80 and 1.00) were studiedin situby high-temperature X-ray diffraction. In this study, the lattice thermal expansion of the six compounds subjected to heat treatments up to 1773 K under reconstituted air (N2+ 21% O2+ ∼5 vpm H2O) was investigated. The materials remained monophasic throughout the experiments and, depending upon the americium content, the lattice parameter of the face-centred cubic phase deviated from linear lattice expansion at elevated temperatures as a result of the progressive reduction of Am4+to Am3+.

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