A Comparative First Principles Study of Phase Stability in Ni-Ti and Ni-Al Alloys Around Equiatomic Composition

1990 ◽  
Vol 186 ◽  
Author(s):  
P.E.A. Turchi ◽  
M. Sluiter ◽  
F.J. Pinski ◽  
D.D. Johnson
Keyword(s):  
Electronic Structure ◽  
Internal Energy ◽  
Phase Stability ◽  
First Principles ◽  
Al Alloys ◽  
Equiatomic Composition ◽  
Potential Approximation ◽  
Dependent Part ◽  
Substitutional Alloys ◽  
Effective Cluster

AbstractElectronic structure and phase stability properties of Ni-Ti and Ni-Al around equiatomic composition are investigated with a first principles approach. The study is based upon the generalized purturbation method applied to the Korringa-Kohn-Rostoker multiple scattering formulation of the coherent potential approximation. Within this framework, effective cluster interactions which build up the configuration-dependent part of the internal energy are calculated. The strength of ordering tendencies in both bcc-based substitutional alloys is compared and contrasted in terms of hybridisation effects, in relation with experimental evidences.

First-Principles Study of Phase Stability in Pd-Rh Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
D.D. Johnson ◽  
P.E.A. Turchi ◽  
Marcel Sluiter ◽  
D.M. Nicholson ◽  
F.J. Pinski ◽  
...  
Keyword(s):  
Phase Separation ◽  
Phase Stability ◽  
First Principles ◽  
Ternary Addition ◽  
Potential Approximation ◽  
Effective Interactions ◽  
Reference Medium ◽  
Random Alloy ◽  
Substitutional Alloys ◽  
Effective Cluster

We present a study of the mixing energies and the effective cluster interactions which form the configurational part of the internal energy of Pd-Rh substitutional alloys. We discuss the tendency towards phase-separation and more generally phase stability. The effects of a substitutional ternary addition on the tendencies toward order or phase-separation are also reported. The Korringa-Kohn-Rostoker Coherent-Potential Approximation (KKR-CPA) is used to investigate the electronic structure effects and energetics of the random alloy. Moreover, we use the Generalized Perturbation Method (GPM), using the KKR-CPA random alloy as a reference medium, to investigate the effective interactions which determine phase stability. We briefly comment on other factors which may give important contributions to the total free-energy of the alloy. We also contrast the GPM with the Connolly-Williams approach for calculating phase diagrams from first-principles. Finally, we explore the inadequacies of the frozen-potential and Harris approximations to the energetics of alloying.

Electronic Structure and Phase Stability Properties of Ai-Li Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
Antonios Gonis ◽  
Patrice E.A. Turchi ◽  
Marcel Sluiter ◽  
Frank J. Pinski ◽  
Duane D. Johnson
Keyword(s):  
Phase Diagram ◽  
Electronic Structure ◽  
Perturbation Method ◽  
Multiple Scattering ◽  
Phase Stability ◽  
First Principles ◽  
Potential Approximation ◽  
Effective Interactions ◽  
Lattice Constants ◽  
Effective Cluster

AbstractRecently, the phase diagram of AI-Li alloys was calculated with the use of the Connolly-Williams method. In an effort to test the validity and to supplement the results of that study, equilibrium lattice constants and effective cluster interactions have been obtained using the generalized perturbation method within the first-principles multiple-scattering formalism of the Korringa-Kohn-Rostoker coherent-potential approximation. The implication of these effective interactions to the phase stability of these alloys is discussed.

Electronic Structure and Phase Stability Properties in Ternary Substitutional Alloys

1992 ◽  
Vol 291 ◽  
Author(s):  
Ariel J.S. Traiber ◽  
Marcel Sluiter ◽  
Patrice E.A. Turchi ◽  
Samuel M. Allen
Keyword(s):  
Electronic Structure ◽  
Tight Binding ◽  
Metal Alloys ◽  
Potential Approximation ◽  
Stability Properties ◽  
Ternary Metal ◽  
Random Alloy ◽  
Method Approach ◽  
Substitutional Alloys ◽  
Effective Cluster

ABSTRACTElectronic structure and stability properties of ternary-metal alloys are examined using an extension of the Coherent Potential Approximation -Generalized Perturbation Method approach within the Tight-Binding description of the chemically random alloy. In particular, we report on calculations of density of states, mixing energies and effective cluster interactions which build up the ordering energy. The study focuses on the Ti-V-Fe system and its binary components.

The stability, electronic structure, elastic and metallic properties of manganese nitrides

RSC Advances ◽  
2015 ◽  
Vol 5 (2) ◽  
pp. 1620-1627 ◽  
Author(s):  
Ran Yu ◽  
Xiaoyu Chong ◽  
Yehua Jiang ◽  
Rong Zhou ◽  
Wen Yuan ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Phase Stability ◽  
First Principles ◽  
First Principles Calculations ◽  
The Stability

The phase stability, electronic structure, and elastic and metallic properties of manganese nitrides (Mn4N, Mn2N0.86, Mn3N2, and MnN) were extensively studied by first principles calculations.

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.

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