Contribution of the vibrational free energy to phase stability in substitutional alloys: Methods and trends

1996 ◽  
Vol 53 (14) ◽  
pp. 8993-9001 ◽  
Author(s):  
G. D. Garbulsky ◽  
G. Ceder
Keyword(s):  
Free Energy ◽  
Phase Stability ◽  
Vibrational Free Energy ◽  
Substitutional Alloys

scholarly journals Vibrational free energy and phase stability of paramagnetic and antiferromagnetic CrN fromab initiomolecular dynamics

2014 ◽  
Vol 89 (17) ◽  
Author(s):  
Nina Shulumba ◽  
Björn Alling ◽  
Olle Hellman ◽  
Elham Mozafari ◽  
Peter Steneteg ◽  
...  
Keyword(s):  
Free Energy ◽  
Phase Stability ◽  
Vibrational Free Energy

Configuration Dependence of the Vibrational Free Energy in Substitutional Alloys and Its Effects on Phase Stability

1995 ◽  
Vol 408 ◽  
Author(s):  
G. D. Garbulsky ◽  
G. Ceder
Keyword(s):  
Free Energy ◽  
Experimental Information ◽  
Model Systems ◽  
Lattice Vibrations ◽  
Chemical Affinity ◽  
Transition Temperatures ◽  
Size Mismatch ◽  
High Frequencies ◽  
Vibrational Free Energy ◽  
Substitutional Alloys

AbstractThe lattice vibrations influence the ordering tendencies in substitutional alloys through the configurational dependence of the vibrational free energy. In this paper we study the size of this effect and the trends with chemical affinity and size mismatch. By analyzing available experimental information and by studying simple model systems for which the phonon frequencies can be easily computed, we find that a) changes in transition temperatures of order-disorder transformations of 30% due to the lattice vibrations may not be uncommon; b) the transition temperatures are usually lowered when the vibrations are included in the modeling of the system, except for certain combinations of size mismatch and chemical affinity; and c) that the largest contribution to the configurational dependence of the vibrational free energy is due to the intermediate and high frequencies of the spectrum.

First-principles investigations on the phase stability, elastic and thermodynamic properties of Zr–Al alloys

2015 ◽  
Vol 26 (12) ◽  
pp. 1550143 ◽  
Author(s):  
Leini Wang ◽  
Songjun Hou ◽  
Dewei Liang
Keyword(s):  
Thermodynamic Properties ◽  
Debye Temperature ◽  
Phase Stability ◽  
First Principles ◽  
Density Functional ◽  
Elastic Wave Velocity ◽  
Electronic Density ◽  
Functional Theory ◽  
High Bulk ◽  
Substitutional Alloys

In this paper, we employ first-principles methods based on electronic density functional theory (DFT) to investigate the phase stability, elastic and thermodynamic properties of Zr – Al binary substitutional alloys which are Zr 3 Al , Zr 2 Al , ZrAl , ZrAl 2 and ZrAl 3. By analyzing the elastic constants and enthalpy of formation, those phases both satisfy the generalized stability criteria and the results show that ZrAl 2 is the most stable. Due to high bulk modulus B, shear modulus G and Youngs modulus Y, ZrAl 2 also possesses excellent mechanical properties. Moreover, it is expected that there will be covalent bonding between Zr and Al atom in ZrAl 2 compound, which is confirmed by the electronic structure and the differences of charge density discussions. In the end, based on the calculated elastic modulus, the elastic wave velocity, Debye temperature ΘD and specific heat CV are discussed. As a result, ZrAl 3 possesses the highest Debye temperature and sound velocity, meaning a larger associated thermal conductivity and higher melting temperature.

A First Principles Examination of Phase Stability in Fcc-Based Ni-V Substitutional Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
J. Mikalopas ◽  
P.E.A. Turchi ◽  
M. Sluiter ◽  
P.A. Sterne
Keyword(s):  
Phase Stability ◽  
Ground State ◽  
First Principles ◽  
Cluster Variation Method ◽  
Variation Method ◽  
Many Body ◽  
Cluster Variation ◽  
Many Body Interactions ◽  
Ground State Energies ◽  
Substitutional Alloys

AbstractThe phase stability of fcc-based Ni-V substitutional alloys is investigated using linear muffin-tin orbitals total energy (LMTO) calculations. The method of Connolly and Williams (CWM) is used to extract many body interactions from the ground state energies of selected ordered configurations. These interactions are used in conjunction with the cluster variation method (CVM) to calculate the alloy phase diagram. The dependence of the interactions on the choice of configurations used to calculate them is examined.

scholarly journals Dynamic allostery of protein alpha helical coiled-coils

2005 ◽  
Vol 3 (6) ◽  
pp. 125-138 ◽  
Author(s):  
Rhoda J Hawkins ◽  
Tom C.B McLeish
Keyword(s):  
Free Energy ◽  
Ligand Binding ◽  
Molecular Motor ◽  
Coiled Coil ◽  
Coiled Coils ◽  
Coarse Grained ◽  
Static Structure ◽  
Change In The Mean ◽  
The Individual ◽  
Vibrational Free Energy

Alpha helical coiled-coils appear in many important allosteric proteins such as the dynein molecular motor and bacteria chemotaxis transmembrane receptors. As a mechanism for transmitting the information of ligand binding to a distant site across an allosteric protein, an alternative to conformational change in the mean static structure is an induced change in the pattern of the internal dynamics of the protein. We explore how ligand binding may change the intramolecular vibrational free energy of a coiled-coil, using parameterized coarse-grained models, treating the case of dynein in detail. The models predict that coupling of slide, bend and twist modes of the coiled-coil transmits an allosteric free energy of ∼2 k B T , consistent with experimental results. A further prediction is a quantitative increase in the effective stiffness of the coiled-coil without any change in inherent flexibility of the individual helices. The model provides a possible and experimentally testable mechanism for transmission of information through the alpha helical coiled-coil of dynein.

First-principles study of phase stability in Cu-Zn substitutional alloys

1991 ◽  
Vol 67 (13) ◽  
pp. 1779-1782 ◽  
Author(s):  
P. E. A. Turchi ◽  
M. Sluiter ◽  
F. J. Pinski ◽  
D. D. Johnson ◽  
D. M. Nicholson ◽  
...  
Keyword(s):  
Phase Stability ◽  
First Principles ◽  
First Principles Study ◽  
Substitutional Alloys
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