• Aucun résultat trouvé

Structure and stability of Fe2

N/A
N/A
Info
Télécharger
Protected

Academic year: 2021

Partager "Structure and stability of Fe2"

Copied!
1
0
0

Chargement.... (Voir le texte intégral maintenant)

Texte intégral

(1)

Structure and stability of Fe

2

(Zr

1-x

Nb

x

) Laves Phases

L. RABAHI1,2, A. Kellou2 and D. BRADAI1

1 Laboratoire physique des matériaux, USTHB B.P.32, El Alia, 16111, Bab Ezzouar, Alger

2 Laboratoire physique théorique, USTHB B.P.32, El Alia, 16111, Bab Ezzouar, Alger

The Laves phase structures (C15, C14 and C36) exist in a large number of binary and ternary intermetallic compounds of composition AB2. Although they are well known since long time ago, there are still unsolved problems concerning the stability of the respective crystal structures. Therefore, it is difficult to predict which of the three structure types is the stable one for a given laves phase compound. In this sense, several calculation methods have been successfully applied to predict the stable ground state structure of various laves phases, but these calculations are restricted to the stoichiometric compositions and at 0 K. However in real systems the stability of laves phase type is a function of temperature and composition and also different Laves phases types may coexist in a single system. This is the subject of the present work, where we applied the quasi harmonic approximation implemented on Gibbs2 program and the Ab initio pseudopotential method to study the temperature and composition- dependence transformations in the Laves phase Fe2(Zr1-x,Nbx) system. The results show a complex behavior with a cyclic variation of the stable structure types as function of temperature and Niobium concentration.

Keywords: Laves Phases, First-Principles calculations, Stability, Heat of Formation, Thermal Properties and Gibbs2 Programm.

Références

Télécharger maintenant ( PDF - 1 Page - 6.91 KB )

Documents relatifs

In the present work, we show that the stability domain of the present scheme is independent of ε

A second scheme is associated with a decentered shock-capturing–type space discretization: the II scheme for the viscous linearized Euler–Poisson (LVEP) system (see section 3.3)..

Where is the Semantics and Where Do We Want it to Be? Let the Flaming Begin!

We have shared large cross-domain knowledge bases [4], enriched them with linguistic and distributional information [7, 5, 2] and created contin- uous evolution feedback loops

Ab-initio Investigation of the Hydrogenation of Y

The stoichiometry of the calculated compounds is Y, YH tetra 2 ; YH 3 and YH octa 1 : Upon placement of hydrogen in tetrahedral sites we note for the YH tetra 2 phase a new,

Ab initio determination and Rietveld refinement of the crystal structure of Ni0.50TiO(PO4)

The present paper reports the synthesis of Ni 0 50 TiO(PO 4 ) and an ab initio determination of crystal structure from the X-ray powder diffraction

For the benefit of the reader, we have been compelled to present this work in a clear and straightforward manner

During this 1906 visit, Rinpoche’s father met the 8 th Khachoed Rinpoche, Drupwang Lungtok Tenzin Palzangpo of Khachoedpalri monastery in West Sikkim, and from

9 The structure of the shuffle and harmonic al- gebras

Recall Corollaries 34 and 36 of Radford and Hoffman concerning the struc- tures of the algebras H x and H � respectively (we take here for ground field K the field R of

We will also present the state of the art on this topic

This conjecture, which is similar in spirit to the Hodge conjecture, is one of the central conjectures about algebraic independence and transcendental numbers, and is related to many

This condition allows the degeneracy only where one of the two phases is exclusively present

Feng, Strong solutions to a nonlinear parabolic system modeling compressible misci- ble displacement in porous media, Nonlinear Anal., Theory Methods Appl., 23 (1994), 1515–1531.