First-principles interatomic potentials for transition-metal aluminides. II. Application to Al-Co and Al-Ni phase diagrams

1998 ◽  
Vol 58 (14) ◽  
pp. 8967-8979 ◽  
Author(s):  
Mike Widom ◽  
John A. Moriarty
Keyword(s):  
Transition Metal ◽  
Phase Diagrams ◽  
First Principles ◽  
Interatomic Potentials ◽  
Metal Aluminides

Cohesion, Compound Formation and Phase Diagrams from First Principles

1982 ◽  
Vol 19 ◽  
Author(s):  
A. R. Williams ◽  
C. D. Gelatt ◽  
J. W. D. Connolly ◽  
V. L. Moruzzi
Keyword(s):  
Transition Metal ◽  
Phase Diagrams ◽  
First Principles ◽  
Formation Process ◽  
Energy Band ◽  
Empirical Formula ◽  
Heats Of Formation ◽  
Disordered Materials ◽  
Compound Formation ◽  
Self Consistent

ABSTRACTThe physical picture of cohesion and compound formation provided by parameter-free, self-consistent, energy-band calculations will be described. For transition-metal elements, the calculations allow us to “see” which electrons are holding the solid together and which are holding it apart. For compounds, calculated heats of formation agree well with available measurements and are in general agreement with those given by Miedema's empirical formula. (The agreement with Miedema is paradoxical, in that Miedema's conception of the formation process differs qualitatively from ours.) Preliminary, but very encouraging, results of efforts to extend the analysis to disordered materials and to the calculation of phase diagrams are described.

Metastability of the o-phase in transition-metal aluminides: First-principles structural predictions

1996 ◽  
Vol 74 (6) ◽  
pp. 1385-1397 ◽  
Author(s):  
D. Nguyen-manh ◽  
D. G. Pettifor ◽  
G. Shao ◽  
A. P. Miodownik ◽  
A. Pasturel
Keyword(s):  
Transition Metal ◽  
First Principles ◽  
Metal Aluminides ◽  
O Phase

Electron energy loss near edge structures of intermetallic alloys and grain boundaries in NiAl

1996 ◽  
Vol 54 ◽  
pp. 522-523
Author(s):  
G.A. Botton ◽  
C.J. Humphreys
Keyword(s):  
High Temperature ◽  
Transition Metal ◽  
Energy Loss ◽  
Grain Boundaries ◽  
Industrial Applications ◽  
Edge Structure ◽  
Structural Applications ◽  
Yield Behaviour ◽  
Late Transition ◽  
Metal Aluminides

Transition metal aluminides are of great potential interest for high temperature structural applications. Although these materials exhibit good mechanical properties at high temperature, their use in industrial applications is often limited by their intrinsic room temperature brittleness. Whilst this particular yield behaviour is directly related to the defect structure, the properties of the defects (in particular the mobility of dislocations and the slip system on which these dislocations move) are ultimately determined by the electronic structure and bonding in these materials. The lack of ductility has been attributed, at least in part, to the mixed bonding character (metallic and covalent) as inferred from ab-initio calculations. In this work, we analyse energy loss spectra and discuss the features of the near edge structure in terms of the relevant electronic states in order to compare the predictions on bonding directly with spectroscopic experiments. In this process, we compare spectra of late transition metal (TM) to early TM aluminides (FeAl and TiAl) to assess whether differences in bonding can also be detected. This information is then discussed in terms of bonding changes at grain boundaries in NiAl.

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