Icosahedral phase formation in rapidly quenched aluminum-ruthenium alloys

1988 ◽  
Vol 3 (3) ◽  
pp. 421-425 ◽  
Author(s):  
Steven M. Anlage ◽  
Brent Fultz ◽  
Kannan M. Krishnan
Keyword(s):  
Electron Microscopy ◽  
Phase Diagram ◽  
Rapid Solidification ◽  
Phase Formation ◽  
Metastable Phase ◽  
Icosahedral Phase ◽  
Rapid Quenching ◽  
Metastable Phase Diagram ◽  
X Ray Diffraction ◽  
X Ray

Systematic rapid quenching experiments on the icosahedral phase-forming system Al1 − xRux were performed for × < 20 at. %. The solidified alloys have been studied by electron microscopy and x-ray diffraction to determine their composition, constituent phases, and phase morphology. It has been determined that the icosahedral phase must form directly from the liquid and, at these quench rates, is always found in the presence of second or third phases. The results have been summarized in a metastable phase diagram appropriate for rapid solidification of Al1 − xRux at piston and anvil quench rates. This metastable phase diagram describes the results for Ru concentrations less than 14 at. %.

Metastable phase diagram of Bi probed by single-energy x-ray absorption detection and angular dispersive x-ray diffraction

2006 ◽  
Vol 74 (6) ◽  
Author(s):  
E. Principi ◽  
M. Minicucci ◽  
A. Di Cicco ◽  
A. Trapananti ◽  
S. De Panfilis ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Metastable Phase ◽  
Metastable Phase Diagram ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Absorption

On the Mechanical Milling of the AlCuFe Icosahedral Phase with Water

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.

Microstructure & Phase Transformation in Rapidly Solidified V-Ga Alloys

1986 ◽  
Vol 80 ◽  
Author(s):  
M. W. Park ◽  
S. H. Whang ◽  
S. Karmarkar ◽  
D. Divecha
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Grain Refinement ◽  
Rapid Solidification ◽  
Rapid Quenching ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rapidly Solidified ◽  
A15 Phase

AbstractThe A15 Phase forming V-Ga alloys were processed into ribbons and foils by rapid solidification techniques. Microstructures and phase transformation in these alloys by rapid solidification and succeeding heat treatment were investigated by x-ray diffraction and TEM. It is shown that equilibrium A15 phases can readily be suppressed by rapid quenching in these alloys. A significant grain refinement resulting from the rapid solidification also was observed. Microhardnesses of these alloys as a function of Ga concentration were determined.

scholarly journals Scanning X-Ray Diffraction: A Technique With High Compositional Resolution for Studying Phase Formation in Co-Deposited Thin Films

1994 ◽  
Vol 343 ◽  
Author(s):  
T.I. Selinder ◽  
D.J. Miller ◽  
K.E. Gray ◽  
M.A. Beno ◽  
G.S. Knapp
Keyword(s):  
Thin Films ◽  
Phase Formation ◽  
Structural Information ◽  
Metastable Phase ◽  
Ternary Systems ◽  
Composition Gradient ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Technique ◽  
Position Sensitive

ABSTRACTInvestigation of the formation of new metastable phases in alloy thin films requires ways of quickly determining the crystalline structure of samples with different compositions. We report a novel technique for acquiring structural information from films intentionally grown with a composition gradient. For example, binary metal alloy films were deposited using a phase-spread sputtering method. In this way essentially the entire composition range could be grown in a single deposition. By using a narrow incident x-ray beam and a translating sample stage combined with a position sensitive x-ray detector technique, detailed information of the metastable phase diagram can be obtained rapidly. Compositional resolution of the order of ±0.2% can be achieved, and is limited by the brightness of the x-ray source. Initial results from studies of phase formation in Zr-Ta alloys will be presented. Extensions of the analysis technique to ternary systems will be discussed.

On the Structural Evolution of the Amorphous Al75Cu15V10 Alloy to the Icosahedral Phase

1988 ◽  
Vol 43 (5) ◽  
pp. 505-506 ◽  
Author(s):  
E. Matsubara ◽  
Y. Waseda ◽  
A. P. Tsai ◽  
A. Inoue ◽  
T. Masumoto
Keyword(s):  
Electron Microscopy ◽  
Structural Evolution ◽  
Icosahedral Phase ◽  
X Ray Diffraction ◽  
Bright Field ◽  
Continuous Growth ◽  
X Ray ◽  
Transmission Electron ◽  
Icosahedral Clusters ◽  
Peak Widths

The transformations occurring on annealing an as-spun amorphous Al75Cu15V10 alloy are studied by X-ray diffraction and transmission electron microscopy (TEM). A continuous growth of icosahedral clusters, which are present already in the as-spun sample, is revealed. The size of the clusters estimated from the diffuse X-ray peak widths is consistent with the size of the modulation observed in the bright field TEM images.

Phase formation sequence induced by deposition temperatures in Nb/Si multilayers

1998 ◽  
Vol 13 (5) ◽  
pp. 1373-1378 ◽  
Author(s):  
Ming Zhang ◽  
W. K. Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Formation ◽  
Room Temperature ◽  
Heat Of Formation ◽  
Silicide Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Phases ◽  
Transmission Electron

The phase formation sequence in Nb/Si multilayers formed at different deposition temperatures was investigated by x-ray diffraction (XRD) and transmission electron microscopy (TEM). The amorphous phases were found to form in Nb/Si multilayers deposited at room temperature and 560 °C, but the compositions of these two amorphous phases were different. The crystalline Nb3Si and Nb5Si3 were formed in Nb/Si multilayers deposited at 180–500 °C. The interfacial energy and modified heat of formation are adopted to explain our obtained results. The occurrence of crystalline Nb5Si3, NbSi2, and amorphous silicide phase was found when the Nb/Si multilayers with Nb3Si phase were annealed at 550 °C, while only NbSi2 was found to form when annealing this sample at 700 °C. The mobility of Si takes an important role in phase formation in Nb/Si multilayers.

scholarly journals Synthesis and stability of quasicrystalline phase in Al-Cu-Fe-Si mechanically alloyed powders

2021 ◽  
Vol 56 (18) ◽  
pp. 11071-11082
Author(s):  
Mikołaj Mitka ◽  
Anna Góral ◽  
Lidia Lityńska-Dobrzyńska
Keyword(s):  
Phase Formation ◽  
Icosahedral Phase ◽  
Quasicrystalline Phase ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Transmission Electron ◽  
20 Nm ◽  
Si Addition ◽  
Thermal Stability Of

AbstractThe effect of Si addition on a quasicrystalline phase formation in Al-Cu-Fe-Si alloys prepared by mechanical alloying has been investigated using X-ray diffraction and scanning and transmission electron microscopy. Two compositions containing 10 at.% of Si were selected to verify the influence of the e/a ratio on a sequence of phase formation during milling: Al58.5Cu18Fe13.5Si10 (e/a = 1.98) and Al53.5Cu19.5Fe17Si10 (e/a = 1.75). A quasicrystalline icosahedral phase (i-phase) was found in both alloys after 10 h of milling in the form of nano-quasicrystallites with the size of 10–20 nm. Addition of Si stabilized the quasicrystalline phase being dominant after prolonged milling time, contrary to the reference ternary Al65Cu20Fe15 powder, which apart of the quasicrystalline phase contained the cubic β-Al(Cu, Fe) phase. Thermal stability of the quasicrystalline phase in the powders milled for 10 h was examined after annealing at 800 °C for 4 h. The i-phase was preserved partially in Al53.5Cu19.5Fe17Si10 and reference Al65Cu20Fe15 powders (both with a ratio e/a = 1.75), which coexisted with β-Al(Cu, Fe) and Al13Fe4 phase or α-Al55Si7Cu25.5Fe12 and Al2Fe3Si3 phases in Al65Cu20Fe15 and Al53.5Cu19.5Fe17Si10, respectively. For the Al58.5Cu18Fe13.5Si10 powders (e/a = 1.98), the annealing led to complete transformation of the i-phase to the cubic α-Al55Si7Cu25.5Fe12.5 approximant, forming crystallites with a size of 100–300 nm. Graphical abstract

Rapid-Quenching Investigation of the Nb-Pd-Ge System

1990 ◽  
Vol 205 ◽  
Author(s):  
C. E. Krill ◽  
W. L. Johnson
Keyword(s):  
Phase Diagram ◽  
Single Phase ◽  
Rapid Quenching ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solubility Range ◽  
Fcc Phase ◽  
Bcc Phase

AbstractThe structure of rapidly quenched Nb100-x-yPdxGey alloys has been investigated using x-ray diffraction. Niobium concentrations were varied between 100 and 45 at.% the remainder at each Nb concentration was composed of Pd and up to y = 15 at.% Ge. Germanium was found to suppress the nucleation rate of the fcc α-NbPd phase relative to that of the bcc α-Nb phase, thereby extending the single-phase bcc solubility range by ≈ 2 at.% Nb. High Ge content (y > 6) also induced quenching of the amorphous phase. These results can be understood from the standpoint of classical nucleation theory and from a consideration of the polymorphic phase diagram of Nb-Pd. The two approaches are consistent with Ge addition depressing the To line of the fcc phase more rapidly than it depresses the To line of the bcc phase.

Solidification of Al–Cu–Fe alloys forming icosahedral phase

1996 ◽  
Vol 11 (9) ◽  
pp. 2177-2185 ◽  
Author(s):  
B. Grushko ◽  
R. Wittenberg ◽  
D. Holland-Moritz
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Differential Thermal Analysis ◽  
Icosahedral Phase ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fe Alloys ◽  
Scanning Electron

The solidification of a series of Al–Cu–Fe alloys containing an icosahedral phase has been studied by scanning electron microscopy, energy-dispersive x-ray spectroscopy, powder x-ray diffraction, and differential thermal analysis. The constitution and morphology of alloys solidified at different rates are presented. The overall compositional range of the icosahedral phase was determined in as-cast, slowly solidified alloys and those annealed at 800 and 600 °C. The solidification of this phase follows closely the Al3Fe–AlCu compositional direction. The first icosahedral phase solidified close to Al65.5Cu21.5Fe13; its compositional region at 800 °C lies between about Al64.5Cu23Fe12.5 and Al62Cu26.5Fe11.5, while at 600 °C it lies between Al62Cu26.5Fe11.5 and Al60.5Cu29.5Fe10. The formation of the icosahedral and related structures observed in Al–Cu–Fe alloys is discussed.

Effect of PO2 and Ag on the phase formation of the Bi(Pb)-2223 superconductor

1999 ◽  
Vol 14 (5) ◽  
pp. 1695-1706 ◽  
Author(s):  
W. Wong-Ng ◽  
L. P. Cook ◽  
W. Greenwood
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Formation ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Samples ◽  
Fraction Mixture ◽  
Precursor Composition ◽  
Scanning Electron

The chemical reactions and the compositional characteristics of liquids which lead to the phase formation of the Bi(Pb)-2223 [(Bi, Pb): Sr: Ca: Cu: O] superconductor have been studied for a precursor composition of Bi1.8Pb0.4Sr2Ca2.2Cu3Ox. The combined techniques of quenching, powder x-ray diffraction, differential thermal/thermogravimetric analysis (DTA/TGA), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS) were used to characterize the subsolidus phases and the presence of liquid. Samples were annealed under purified air and under a volume fraction mixture of 7.5% O2/92.5% Ar. The effects of Ag in both the pure air and the 7.5% O2/92.5% Ar experiments were also studied. Results are discussed with respect to their processing implications.

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