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.

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.

A Tight-Binding Hamiltonian for the High-Temperature Superconductor YBa2Cu3O7

1988 ◽  
Vol 141 ◽  
Author(s):  
M.J. DeWeert ◽  
D.A. Papaconstantopoulos ◽  
W.E. Pickett
Keyword(s):  
Electronic Structure ◽  
High Temperature ◽  
Band Structure ◽  
Potential Application ◽  
Oxygen Vacancies ◽  
High Temperature Superconductor ◽  
Tight Binding ◽  
Coherent Potential Approximation ◽  
Potential Approximation

AbstractWe present a highly accurate tight-binding parametrization of the LAPW band structure of the high-temperature superconductor YBa2Cu3O7, discuss the methodology used in obtaining this fit, and its potential application to a Tight-Binding Coherent-Potential Approximation (TB-CPA) calculation of the effects of oxygen vacancies on the electronic structure.

scholarly journals Electronic Structure of Substitutionally Disordered Alloys: Direct Configurational Averaging

1992 ◽  
Vol 278 ◽  
Author(s):  
C. Wolverton ◽  
D. De Fontaine ◽  
H. Dreysse ◽  
G. Ceder
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Local Density ◽  
Tight Binding ◽  
Ternary Alloys ◽  
Orbital Method ◽  
Thermodynamic Quantities ◽  
Local Density Of States ◽  
Disordered Alloys ◽  
Effective Cluster

AbstractThe method of direct configurational averaging (DCA) has been proposed to study the electronic structure of disordered alloys. Local density of states and band structure energies are obtained by averaging over a small number of configrations within a tight-binding Hamiltonian. Effective cluster interactions, the driving quantities for ordering in solids, are computed for various alloys using a tight-binding form of the linearized muffin-tin orbital method (TB-LMTO). The DCA calculations are used to determine various energetic and thermodynamic quantities for binary and ternary alloys.

Phase Diagrams and Diffuse Neutron Scattering

1989 ◽  
Vol 166 ◽  
Author(s):  
Rene Caudron ◽  
Maurice Sarfati ◽  
Alphonse Finel ◽  
Francine Solal
Keyword(s):  
Electronic Structure ◽  
Phase Diagrams ◽  
Electronic Structure Calculations ◽  
Interatomic Potentials ◽  
Antiphase Boundaries ◽  
Potential Approximation ◽  
Order Energy ◽  
Random Alloy ◽  
Structure Calculations ◽  
Diffuse Neutron

The order or segregation properties of compounds or solid solutions are important ingredients of the phase diagrams. If the order can be described as an atomic distribution on an underlying lattice, and if the interactions can be expressed in terms of pairs and other multiplet potentials between the atomic species, phase diagrams should be deducible from these potentials, along with other properties, such as antiphase boundaries, core structures of the dislocations in ordered compounds&; This approach, i.e. the very existence of the potentials, is legitimated by electronic structure calculations for or alloys of normal [1] and transition metals [2]. The G.P.M. (General perturbation Method) allows indeed to develop the order energy in terms of interatomic potentials, the reference state, namely the random alloy, being calculated within the C.P.A. (Coherent Potential Approximation).

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.

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