Phase Diagrams And Approximants

MRS Proceedings ◽

10.1557/proc-553-95 ◽

1998 ◽

Vol 553 ◽

Cited By ~ 7

Author(s):

M. Quiquandon ◽

Y. Calvayrac ◽

A. Quivy ◽

F. Faudot ◽

D. Gratias

Keyword(s):

Phase Diagram ◽

Orthorhombic Phase ◽

Ternary Systems ◽

Icosahedral Phase ◽

Quasicrystalline Phase ◽

Quaternary Phase ◽

Cubic Phases ◽

Single Grain ◽

Si Content ◽

P Type

AbstractThe controled growth of large single grain of quasicrystalline phase in metallic alloys is a difficult task that requires a detailled knowledge of the corresponding phase diagram. We discuss the metallurgical specificities of the ternary systems AlCuFe and AlPdMn with respect to single icosahedral grain elaboration. We show that adding a few percents of Silicon in the AlCuFe system leads to stabilize two low order cubic approximants one, α, based on Bergman clusters with a parent F-type icosahedral phase and the other, α', based on Mackay clusters with a parent P-type icosahedral phase. A section of this quaternary phase diagram at constant Si content shows that these cubic phases have no common stability region but are located on opposite sides of an orthorhombic phase that is expected to be a complex synthetic structure mixing both Mackay and Bergman type atomic clusters.

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Quasicrystalline Phase Transformation in the Quaternary and Ternary Systems AlCuMnFe and AlPdMn

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.172-174.941 ◽

2011 ◽

Vol 172-174 ◽

pp. 941-946

Author(s):

Jean Tristan Beauchesne ◽

Daniel Caillard ◽

Marianne Quiquandon ◽

Denis Gratias

Keyword(s):

Phase Diagram ◽

Structural Model ◽

Ternary Systems ◽

Quaternary Alloy ◽

Icosahedral Phase ◽

Rapid Quenching ◽

Quasicrystalline Phase ◽

Fold Axis ◽

Decagonal Phase ◽

The One

An uniﬁed structural model has been devised [1] that describes both icosahedral phasesi-AlPdMn and i-AlCuFe. The model suggests that possible icosahedral structures could be found inalloys with general composition Al61:8(PdjCu)21:35(MnjFe)8:29(AljFejMn)4:28(AljCu)4:28. Applied to the systems AlCuMnFe [2] and AlPdFe [3], thisformula leads to the compositions Al66:08Cu21:35Mn8:29Fe4:28 and Al70:36Pd21:35Fe8:29 that have bothbeen synthetized by rapid quenching and annealing.The as-quenched quaternary alloy Al66:08Cu21:35Mn8:29Fe4:28 exhibits a F-icosahedral phase that trans-forms into a decagonal phase after annealing. Its 10-fold axis aligns along one of the 5-fold axes ofthe icosahedral phase. This implies a group-subgroup transformation, with the kernel group ̅5m, anal-ogous to the one observed during CFC to HCP transformations, with kernel ̅3m.The as-quenched and annealed ternary alloy Al70:36Pd21:35Fe8:29 is similar to i-AlPdMn with an iso-morphic substitution of Mn with Fe. A study of the phase diagram of the system AlPdFe [3] showsthat the results are compatible with the structural model proposed here in strong relations with thosepresented in [1] for i-AlPdMn.

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Processing Of Al-Cu-Fe Quasicrystalline Single Grains

MRS Proceedings ◽

10.1557/proc-553-3 ◽

1998 ◽

Vol 553 ◽

Cited By ~ 1

Author(s):

T. A. Lograsso ◽

A. R. Ross

Keyword(s):

Hot Isostatic Pressing ◽

Icosahedral Phase ◽

Quasicrystalline Phase ◽

Second Phase ◽

Slow Cooling ◽

History Of ◽

Single Grain ◽

A Minor ◽

High Degree ◽

Minor Quantity

AbstractThe phase equilibria of the Al-Cu-Fe quasicrystalline phase (y phase) is complex and conventional crystal growth techniques like the Bridgman and Czochralski methods are not applicable in preparation of large crystals. Large single grains of the y phase been have prepared by either slow cooling or isothermal anneals. In the later technique, arc melted ingots were subjected to either single or multiple heat treatments between 825 and 840°C to encourage grain growth. Following heat treatment, grains of the icosahedral phase are found either as isolated pentagonal-faceted crystals within the ingot or within clusters of intergrown grains. The growth of the large grains is independent of the sample processing history of the sample, is facilitated by the presence of liquid at the growth temperatures and is constrained by the physical dimension of the ingot. The microstructure of both grain types is similar containing a minor quantity (on the order of 5–10 %) of a second phase and a high degree of porosity in the as-grown state. The second phase is usually present as a thin layer between adjacent grains or associated with a pore within a single grain. The grain porosity is distributed throughout the ingot. These defects can be removed through post-growth hot isostatic pressing and anneal treatments.

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Local Order in Single Grain Cd-Yb Icosahedral Phase

MRS Proceedings ◽

10.1557/proc-805-ll7.4 ◽

2003 ◽

Vol 805 ◽

Author(s):

Y. Q. Wu ◽

M. J. Kramer ◽

T. A. Lograsso

Keyword(s):

Cluster Structure ◽

Icosahedral Phase ◽

Quasicrystalline Phase ◽

Local Order ◽

Local Cluster ◽

Transmission Electron Microcopy ◽

Transmission Electron ◽

Single Grain ◽

Matching Rules ◽

D Model

ABSTRACTSingle grains of icosahedral Cd84Yb16 quasicrystalline phase were characterized using high resolution transmission electron microcopy (HRTEM) technique. Image reconstruction of the obtained multiple through-focal series for both the two and five-fold axes are consistent with the local cluster structure of concentric polyhedra consisting of Cd tetrahedron (1/3 occupied icosahedron), Cd dodecahedron, Yb icosahedron and a Cd icosidodecahedron. Edge-sharing of the clusters can result in complete tiling of the 2-D projections. Simple matching rules are being investigated to construct a 3-D model.

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Microstructural Characterization and Phase Diagram Calculation of a Less Known Al–Fe–Mn–Si Phase in a SiCp/2014Al Composite

Microscopy and Microanalysis ◽

10.1017/s1431927619000618 ◽

2019 ◽

Vol 25 (4) ◽

pp. 859-865

Author(s):

Ying Hu ◽

Qiubao Ouyang ◽

Bingbing Zhao ◽

Lanting Zhang

Keyword(s):

Phase Diagram ◽

Hot Extrusion ◽

Microstructural Characterization ◽

Ternary Systems ◽

Nominal Composition ◽

X Ray Diffraction ◽

Wavelength Dispersive Spectroscopy ◽

Selected Area Electron Diffraction ◽

The Matrix ◽

Si Content

AbstractA systematic characterization of a less known Al, Fe, Mn, and Si phase in a SiC particulate-reinforced 2014Al composite (SiCp/2014Al) was performed. In addition to the expected CuAl2 phase, the Al, Fe, Mn, and Si phase was formed as either an adhesion (>1 µm) onto SiC in the as-cast composite, or as a precipitate (<100 nm) in the matrix after hot extrusion. The structure of the phase was identified as cubic by both X-ray diffraction and selected area electron diffraction (SAED). The SAED pattern also indicated that the structure belongs to the Pm$\bar{3}$ space group instead of Im$\bar{3}$. The thermodynamic phase diagram was calculated, confirming the presence of an α-AlFeMn or α-AlFeSi phase in the Al–Fe–Mn and Al–Fe–Si ternary systems, respectively, within the Fe, Mn, and Si content range corresponding to 2014Al. Wavelength-dispersive spectroscopy analysis indicated that the composition of the phase is close to Al12(Fe, Mn)3Si2, in which the Mn/Fe ratio is in the range of 0.6–1.4. The determined Mn/Fe ratio corresponds to the nominal composition of Mn and Fe in the alloy.

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X-RAY STUDY OF CUBIC PHASES IN TERNARY SYSTEMS OF SURFACTANT DDAB, WATER AND OIL

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1990703 ◽

1990 ◽

Vol 51 (C7) ◽

pp. C7-25-C7-34 ◽

Cited By ~ 3

Author(s):

P. BAROIS ◽

D. EIDAM ◽

S. T. HYDE

Keyword(s):

Ternary Systems ◽

X Ray ◽

Cubic Phases

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Calculation of phase diagrams and thermodynamic properties of 14 additive and reciprocal ternary systems containing Li2CO3, Na2CO3, K2CO3, Li2SO4, Na2SO4, K2SO4, LiOH, NaOH, and KOH

Canadian Journal of Chemistry ◽

10.1139/v84-078 ◽

1984 ◽

Vol 62 (3) ◽

pp. 457-474 ◽

Cited By ~ 19

Author(s):

A. D. Pelton ◽

C. W. Bale ◽

P. L. Lin

Keyword(s):

Phase Diagram ◽

Thermodynamic Properties ◽

Molten Salt ◽

Phase Diagrams ◽

Binary Systems ◽

Ternary Phase ◽

Ternary Phase Diagram ◽

Ternary Systems ◽

Maximum Error ◽

Critical Assessment

Phase diagrams and thermodynamic properties of five additive molten salt ternary systems and nine reciprocal molten salt ternary systems containing the ions Li+, Na+, [Formula: see text], OH− are calculated from the thermodynamic properties of their binary subsystems which were obtained previously by a critical assessment of the thermodynamic data and the phase diagrams in these binary systems. Thermodynamic properties of ternary liquid phases are estimated from the binary properties by means of the Conformal Ionic Solution Theory. The ternary phase diagrams are then calculated from these thermodynamic properties by means of computer programs designed for the purpose. It is found that a ternary phase diagram can generally be calculated in this way with a maximum error about twice that of the maximum error in the binary phase diagrams upon which the calculations are based. If, in addition, some reliable ternary phase diagram measurements are available, these can be used to obtain small ternary correction terms. In this way, ternary phase diagram measurements can be smoothed and the isotherms drawn in a thermodynamically correct way. The thermodynamic approach permits experimental data to be critically assessed in the light of thermodynamic principles and accepted solution models. A critical assessment of error limits on all the calculated ternary diagrams is made, and suggestions as to which composition regions merit further experimental study are given.

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Annealing effect on the optical and photoelectrochemical properties of lead oxide

The European Physical Journal Applied Physics ◽

10.1051/epjap/2018180263 ◽

2018 ◽

Vol 84 (3) ◽

pp. 30301 ◽

Cited By ~ 2

Author(s):

Wided Zerguine ◽

Djamila Abdi ◽

Farid Habelhames ◽

Meriem Lakhdari ◽

Hassina Derbal-Habak ◽

...

Keyword(s):

Lead Oxide ◽

Orthorhombic Phase ◽

Heat Treatments ◽

Photoelectrochemical Properties ◽

X Ray Diffraction ◽

Vis Spectroscopy ◽

Size And Morphology ◽

Two Phases ◽

P Type ◽

The Relationship

Effect of the annealing oxidation time of electrodeposited lead (Pb) on the phase formation of lead oxide (PbO) films is reported. The phase structure, optical properties, size and morphology of the films were investigated by scanning electron microscopy, X-ray diffraction and UV-vis spectroscopy. The relationship between structur and photoelectrochemical properties was investigated. Thin films of PbO produced via air annealing of electrodeposited lead consist of a mixture of two phases, orthorhombic (o-PbO) and tetragonal (t-PbO), that determine the material properties and effectiveness as absorber layer in a photoelectrochemical device. The proportion of tetragonal t-PbO increases for longer heat treatments. After 40 h, the sample consists mainly of tetragonal t-PbO. The p-type semiconducting behavior of lead oxide was studied by photocurrent measurements. Different heat treatments yield variations in the ratio of tetragonal to orthorhombic lead oxide that effect on device performances, where devices with a higher content of tetragonal t-PbO show higher photocurrent than with the orthorhombic phase.

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On the Mechanical Milling of the AlCuFe Icosahedral Phase with Water

Materials Science Forum ◽

10.4028/www.scientific.net/msf.793.23 ◽

2014 ◽

Vol 793 ◽

pp. 23-27

Author(s):

C. Patiño-Carachure ◽

J. Luis López-Miranda ◽

F. de la Rosa ◽

M. Abatal ◽

R. Pérez ◽

...

Keyword(s):

Electron Microscopy ◽

Milling Time ◽

Induction Furnace ◽

Icosahedral Phase ◽

Quasicrystalline Phase ◽

X Ray Diffraction ◽

Cast Sample ◽

X Ray ◽

Transmission Electron ◽

Icosahedral Quasicrystalline

In this investigation the Al64Cu24Fe12 alloy was melted in an induction furnace and solidified under normal casting conditions. The as-cast sample was subject to a heat treatment at 700 oC under argon atmosphere in order to obtain the icosahedral quasicrystalline phase in a monophase region. Subsequently, the icosahedral phase was milled for different times and water added conditions. The pre-alloyed and milled powders were characterized using scanning electron microscopy, X-Ray diffraction, and transmission electron microscopy. The experimental results showed that the icosahedral phase is sensitive to the reaction between water and aluminum of the quasicrystalline alloy to generate hydrogen. As the milling time and the amount of water are increased, the embrittlement reaction of the alloy is accentuated releasing more hydrogen.

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