Light Metal Systems. Part 2: Selected Systems from Al-Cu-Fe to Al-Fe-Ti

459 Pages·2005·4.3 MB·English

by  G. Effenberg

Intro d u c t i o n XI
Introduction
Data Covered
The seriesfocuses on light metal ternary systems and includes phase equilibria of importance for alloy
development, processing or application, reporting on selected ternary systems of importance to industrial
light alloy development and systems which gained otherwise scientific interest in the recent years.
General
The series provides consistent phase diagram descriptions for individual ternary systems. The
representation of the equilibria of ternary systems as a function of temperature results in spacial diagrams
whose sections and projections are generally published in the literature. Phase equilibria are described in
terms of liquidus, solidus and solvus projections, isothermal and pseudobinary sections; data on invariant
equilibria are generally given in the form of tables.
The world literature is thoroughly and systematically searched back to the year 1900. Then, the
published data are critically evaluated by experts in materials science and reviewed. Conflicting information
is commented upon and errors and inconsistencies removed wherever possible. It considers those, and only
those data, which are firmly established, comments on questionable findings and justifies re-interpretations
made by the authors of the evaluation reports.
In general, the approach used to discuss the phase relationships is to consider changes in state and phase
reactions which occur with decreasing temperature. This has influenced the terminology employed and is
reflected in the tables and the reaction schemes presented.
The system reports present concise descriptions and hence do not repeat in the text facts which can
clearly be read from the diagrams. For most purposes the use of the compendium is expected to be self-
sufficient. However, a detailed bibliography of all cited references is given to enable original sources of
information to be studied if required.
Structure of a System Report
The constitutional description of an alloy system consists of text and a table/diagram section which are
separated by the bibliography referring to the original literature (see Fig. 1). The tables and diagrams carry
the essential constitutional information and are commented on in the text if necessary.
Where published data allow, the following sections are provided in each report:
Literature Data
The opening text reviews briefly the status of knowledge published on the system and outlines the
experimental methods that have been applied. Furthermore, attention may be drawn to questions which are
still open or to cases where conclusions from the evaluation work modified the published phase diagram.
Binary Systems
Where binary systems are accepted from standard compilations reference is made to these compilations.
In other cases the accepted binary phase diagrams are reproduced for the convenience of the reader. The
selection of the binary systems used as a basis for the evaluation of the ternary system was at the discretion
of the assessor.
Landolt-Börnstein MSIT®
New Series IV/11A2
XII Introduction
Heading
Literature Data
Binary Systems
Solid Phases
Pseudobinary Systems
Invariant Equilibria
Text
Liquidus, Solidus, Solvus Surfaces
Isothermal Sections
Temperature-Composition Sections
Thermodynamics
Materials Properties and Applications
Miscellaneous
References
Miscellaneous
Materials Properties and Applications
Thermodynamics
Temperature-Composition Sections
Tables and Isothermal Sections
diagrams
Liquidus, Solidus, Solvus Surfaces
Invariant Equilibria
Pseudobinary Systems
Solid Phases
Binary Systems
Fig. 1: Structure of a system report
Solid Phases
The tabular listing of solid phases incorporates knowledge of the phases which is necessary or helpful
for understanding the text and diagrams. Throughout a system report a unique phase name and abbreviation
is allocated to each phase.
Phases with the same formulae but different space lattices (e.g. allotropic transformation) are
distinguished by:
– small letters (h), high temperature modification (h > h )
2 1
(r), room temperature modification
(1), low temperature modification (l > l )
1 2
– Greek letters, e.g., (cid:74),(cid:74)'
– Roman numerals, e.g., (I) and (II) for different pressure modifications.
In the table “Solid Phases” ternary phases are denoted by * and different phases are separated by
horizontal lines.
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Intr o d u c t i o n XIII
Pseudobinary Systems
Pseudobinary sections describe equilibria and can be read in the same way as binary diagrams. The notation
used in pseudobinary systems is the same as that of vertical sections, which are reported under
“Temperature-Composition Sections”.
Invariant Equilibria
The invariant equilibria of a system are listed in the table “Invariant Equilibria” and, where possible, are
described by a constitutional “Reaction Scheme” (Fig. 2).
The sequential numbering of invariant equilibria increases with decreasing temperature, one numbering
for all binaries together and one for the ternary system.
Equilibria notations are used to indicate the reactions by which phases will be
– decomposed (e- and E-type reactions)
– formed (p- and P-type reactions)
– transformed (U-type reactions)
For transition reactions the letter U (Übergangsreaktion) is used in order to reserve the letter T to denote
temperature. The letters d and D indicate degenerate equilibria which do not allow a distinction according
to the above classes.
Liquidus, Solidus, Solvus Surfaces
The phase equilibria are commonly shown in triangular coordinates which allow a reading of the
concentration of the constituents in at.%. In some cases mass% scaling is used for better data readability
(see Figs. 3 and 4).
In the polythermal projection of the liquidus surface, monovariant liquidus grooves separate phase
regions of primary crystallization and, where available, isothermal lines contour the liquidus surface (see
Fig. 3).
Isothermal Sections
Phase equilibria at constant temperatures are plotted in the form of isothermal sections (see Fig. 4).
Temperature – Composition Sections
Non-pseudobinary T-x sections (or vertical sections, isopleths, polythermal sections) show the phase
fields where generally the tie lines are not in the same plane as the section. The notation employed for the
latter (see Fig. 5) is the same as that used for binary and pseudobinary phase diagrams.
Thermodynamics
Experimental ternary data are reported in some system reports and reference to thermodynamic
modelling is made.
Notes on Materials Properties and Applications
Noteworthy physical and chemical materials properties and application areas are briefly reported if they
were given in the original constitutional and phase diagram literature.
Miscellaneous
In this section noteworthy features are reported which are not described in preceding paragraphs. These
include graphical data not covered by the general report format, such as lattice spacing – composition data,
p-T-x diagrams, etc.
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XIV Introduction
e
bl
a
reactiontemperatureof 261°C monovariantequilibrium stdown to lowtemperatures secondternaryeutecticreaction
Bi)
g e5+ (
Bi-A 1 Ag)
26 ((cid:156)
l
m
u
m
ctic reactionternary maxiature) Ag-Tl-Bi 294e(max)2L (Ag) + TlBi(cid:156)3 L + TlBi (Ag) + (Tl)(h)289U(cid:156)31 (Ag) + (Tl)(h) + TlBi289e(min)34L (Ag) + (Tl)(h)(cid:156) 207e(max)6L (Ag) + TlBi(cid:156)23 L (Ag)+(Bi)+TlBi197E(cid:156)231 Bi(Ag)+(Bi)+Tl23 L (Ag)+TlBi+TlBi188E(cid:156)3232 (Ag)+TlBi+TlBi323 (Tl)(h) TlBi + (Tl)(r),(Ag)144D(cid:156)31 (Ag)+(Tl)(r)+TlBi3 equation of eutectoidreaction at 144°C
uteper
first binary e(highest tem Tl-Bi 303e1 (Tl)(h)+TlBi(cid:156)3 202e7 (Bi)+TlBi(cid:156)23 192e8 TlBi+TlBi(cid:156)323 44e9h) TlBi+(Tl)(r)(cid:156)3 cheme
l l l 1 Tl)( on s
( cti
ond binaryectic reaction Ag-Tl 291e3l (Ag)+(Tl)(h)(cid:156) 234d1(Tl)(h) (Tl)(r),(Ag)(cid:156) Figure 2: Typical rea
ecut
se
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Intro d u c t i o n XV
C
Data / Grid: at.%
Axes: at.%
δ
p
1 700
20
80
500°C isotherm, temperature is usualy in °C
primaryγ-crystallization γ 500
40 400°C 60 liquidus groove to
decreasing temperatures
binary invariant 40
0
reaction 300 estimated 400°C isotherm
e
2 U e
ternary invariant 60 140
reaction
00 β(h)
3
80 400 α 300 E 400 500 700 20
limit of known region
A 20 40 60 80 B
Fig. 3: Hypothetical liquidus surface showing notation employed
C
Data / Grid: mass%
Axes: mass%
phase field notation
estimated phase boundary γ
20
80
γ+β(h)
40
60
phase boundary three phase field
(partially estimated)
experimental points
L+γ (occasionally reported)
60
40
tie line L+γ+β(h)
80 L β(h)
20
L+β(h)
L+α limit of known region
α
Al 20 40 60 80 B
Fig. 4: Hypothetical isothermal section showing notation employed
Landolt-Börnstein MSIT®
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XVI Introduction
750
L phase field notation
C 500
°
e,
ur
at
er
p
m
Te L+α 32.5% L+β(h) concentration of
abscissa element
250
L+α+β(h) β(h) temperature, °C
β(h) - high temperature
188 modification
α β(r) - room temperature
modification
α+β(h) β(r)
alloy composition
in at.%
0
A 80.00 60 40 20 A 0.00
B 0.00 B 80.00
C 20.00 Al, at.% C 20.00
Fig. 5: Hypothetical vertical section showing notation employed
References
The publications which form the bases of the assessments are listed in the following manner:
[1974Hay] Hayashi, M., Azakami, T., Kamed, M., “Effects of Third Elements on the Activity of Lead
in Liquid Copper Base Alloys” (in Japanese), Nippon Kogyo Kaishi, 90, 51-56 (1974) (Experimental,
Thermodyn., 16)
This paper, for example, whose title is given in English, is actually written in Japanese. It was published
in 1974 on pages 51- 56, volume 90 of Nippon Kogyo Kaishi, the Journal of the Mining and Metallurgical
Institute of Japan. It reports on experimental work that leads to thermodynamic data and it refers to 16 cross-
references.
Additional conventions used in citing are:
# to indicate the source of accepted phase diagrams
* to indicate key papers that significantly contributed to the understanding of the system.
Standard reference works given in the list “General References” are cited using their abbreviations and
are not included in the reference list of each individual system.
MSIT® Landolt-Börnstein
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Int r o d u c t i o n XVII
General References
[C.A.] Chemical Abstarts - pathways to published research in the world's journal and patent
literature - http://www.cas.org/
[Curr.Cont.] Current Contents - bibliographic multidisciplinary current awareness Web resource -
http://www.isinet.com/products/cap/ccc/
[E] Elliott, R.P., Constitution of Binary Alloys, First Supplement, McGraw-Hill, New York
(1965)
[G] Gmelin Handbook of Inorganic Chemistry, 8th ed., Springer-Verlag, Berlin
[H] Hansen, M. and Anderko, K., Constitution of Binary Alloys, McGraw-Hill, New York
(1958)
[L-B] Landolt-Boernstein, Numerical Data and Functional Relationships in Science and
Technology (New Series). Group 3 (Crystal and Solid State Physics), Vol. 6, Eckerlin, P.,
Kandler, H. and Stegherr, A., Structure Data of Elements and Intermetallic Phases (1971);
Vol. 7, Pies, W. and Weiss, A., Crystal Structure of Inorganic Compounds, Part c, Key
Elements: N, P, As, Sb, Bi, C (1979); Group 4: Macroscopic and Technical Properties of
Matter, Vol. 5, Predel, B., Phase Equilibria, Crystallographic and Thermodynamic Data of
Binary Alloys, Subvol. a: Ac-Au ... Au-Zr (1991); Springer-Verlag, Berlin.
[Mas] Massalski, T.B. (Ed.), Binary Alloy Phase Diagrams, ASM, Metals Park, Ohio (1986)
[Mas2] Massalski, T.B. (Ed.), Binary Alloy Phase Diagrams, 2nd edition, ASM International,
Metals Park, Ohio (1990)
[P] Pearson, W.B., A Handbook of Lattice Spacings and Structures of Metals and Alloys,
Pergamon Press, New York, Vol. 1 (1958), Vol. 2 (1967)
[S] Shunk, F.A., Constitution of Binary Alloys, Second Supplement, McGraw-Hill, New York
(1969)
[V-C] Villars, P. and Calvert, L.D., Pearson's Handbook of Crystallographic Data for
Intermetallic Phases, ASM, Metals Park, Ohio (1985)
[V-C2] Villars, P. and Calvert, L.D., Pearson's Handbook of Crystallographic Data for
Intermetallic Phases, 2nd edition, ASM, Metals Park, Ohio (1991)
Landolt-Börnstein MSIT®
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Al–Cu–Fe 1
Aluminium – Copper – Iron
Cui Ping Wang, Xing Jun Liu, Liming Zhang, Kiyohito Ishida
Literature Data
Critical evaluation of constitutional data in the Al-Cu-Fe system has been done by [1991Leg] covering the
then known literature. The present evaluation updates and amends this work within the same evaluation
program. The investigations on the phase equilibria in the Al-rich portion have been carried out by
[1924Fue, 1925Got, 1928Arc, 1928Gwy, 1932Yam, 1933Rol, 1934Fue, 1939Bra2, 1939Nis, 1940Fin,
1940Hun, 1940Shi, 1940Wie, 1941Bro, 1948Sha, 1950Phr, 1952Han, 1954Phi, 1984Ben, 1992Gay1,
1992Gay2, 1992Zak, 1993Fau1, 1993Fau2, 2000Yok1, 2000Yok2, 2000Yok3, 2001Ros], and two reviews
have been presented by [1961Phi] and [1976Mon]. The Cu-rich equilibria have been studied by [1938Nis,
1939Bra1, 1941Yut] and [1952Haw] and the Fe-rich equilibria by [1939Bra1]. The effect of small amount
of Fe on the phase equilibria in the Al-Cu alloys was reported by [2001Liu], and that of Cu on site
occupancy and diffusion behavior in the Al-Fe alloys was studied by [1997And, 2002Ban] and [1998Akd],
respectively. [1997Oht] determined the liquid/solid equilibria in the Cu-Fe side on the basis of
thermodynamic calculation and diffusion couple technique, and the extensive investigation of [1997Oht]
was continued by [1998Wan], in which solid/solid equilibria and an order-disorder transition of the bcc
phase are included. More recently, [2002Zha, 2003Zha1, 2003Zha2, 2003Zha3, 2003Zha4] carried out
detailed experimental investigations of the phase equilibria in the Al-rich portion around the icosahedral
quasicrystalline phase region on the basis of the techniques of differential thermal analysis, magnetothermal
analysis, scanning electron microscopy and X-ray diffraction. [2003Mie] presented a thermodynamic
assessment for the phase equilibria in the Cu-Fe side portion.
The different fields of crystallization are proposed by [1939Bra2] and [1971Pre], but in [1939Bra2] the
phase (cid:45) is missing and in [1971Pre] the compositions given are not in good agreement with their published
1
diagram. General studies about the system have been proposed by [1935Bos, 1936Bra, 1940Bra, 1955Tur,
1956Spe, 1969LeM, 1972Miu, 1972Pro, 1973Kow, 1975Wac, 1978Pan1, 1981Bre] and [1987Str]. In
particular, in the past decade, enormous investigations on crystal structure and physical and mechanical
properties of icosahedral quasicrystalline phase have been performed by [1991Aud1, 1991Aud2, 1991Bes,
1991Che1, 1991Che2, 1991Fau, 1991Jan, 1991Men, 1991Lei, 1991Liu1, 1991Liu2, 1991Qui, 1991Wu,
1991Zha, 1992Che1, 1992Che2, 1992Eib, 1992Mat, 1992Nas, 1993Ban, 1993Bes, 1993Lee, 1993Men,
1993Was, 1994Bes, 1994Fre1, 1994Fre2, 1994Law, 1994Lef, 1995Div, 1996Qui, 1997Div, 1997Ham,
1997Pop, 1997Ros, 1997She, 1998Dun, 1998Ma, 2000Bou, 2000Dun, 2000Gre1, 2000Gre2, 2000Jon,
2000Nak, 2000Sha, 2000Ste, 2000Uch, 2001Bar, 2001Cai, 2001Gui, 2001Jon, 2001Sur, 2001Guo,
2002Hir, 2002Gre, 2002Kra, 2002Sha].
Binary Systems
The Al-Cu binary system was reviewed by [1985Mur], and has been adopted from [1994Mur] with
modification of [1998Liu], where it is found that earlier reported phase (cid:7) does not exist, and the earlier
0
reported two-phase equilibrium ((cid:11) +(cid:11) ) was determined as second order reaction (cid:11) -(cid:11) in the composition
0 1 1 0
range of 62-68 at.% Cu. The Al-Fe and Cu-Fe binary systems have been accepted from [1993Kat] and
[2001Tur], respectively.
Solid Phases
Data on all solid phases are given in Table 1. The existence of a stable single icosahedral quasicrystalline
phase ((cid:45)) has been reported for the first time by [1987Tsa1] and [1987Tsa2] and later on by a series of
i
research groups [1988Bou, 1988Hir, 1988Ish, 1988Tsa, 1989Dev, 1989Don, 1989Eba]. The formation
range of the icosahedral phase found by [1987Tsa1] is close to the composition range of a ternary phase
discovered by [1939Bra2] and referred to as (cid:53) phase (about 20 to 26 at.% Cu and 12 to 13 at.% Fe) the
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2 Al–Cu–Fe
structure of which was left unidentified. [1990Cal] has demonstrated that the (cid:53) phase is indeed the
icosahedral phase. Following [1990Fau1, 1991Fau], the composition range of the icosahedral phase is
around Fe Cu Al . [1939Bra2, 1989Don, 1990Fau1, 2000Yok1, 2000Yok2] and [2003Zha1] agree
12.5 25.5 62
that the icosahedral (cid:45) phase formation proceeds following a peritectic reaction.
i
There is also a general agreement that the Al-Cu-Fe icosahedral phase corresponds to an F type structure
which can be seen as an ordered F superstructure of the primitive six dimensional (6D) hypercubic lattice
[1988Ish, 1989Dev, 1989Eba] and exists as a single phase stable at 800°C. At lower temperatures (about
600°C) the structure strongly depends on the composition of the alloy. For compositions around
Fe Cu Al the icosahedral phase is perfect, without phasons and without any modification even after
12.5 25.5 62
annealing for 4 days at 500°C.
For compositions different but close to this domain, either a modulated structure appears [1991Aud1] or
even a transformation towards periodic phases (rhombohedral) [1990Den]. Further investigations of crystall
structure with an emphasis of phase transition and thermal stability of Al-Cu-Fe quasicrystalline in bulk and
layer states have been carried out by many groups on the basis of experiment and theory [1991Aud1,
1991Aud2, 1991Bes, 1991Che, 1991Dub, 1991Eib, 1991Fau, 1991Jan, 1991Lei, 1991Liu1, 1991Liu2,
1991Men, 1991Wu, 1991Zha, 1992Che1, 1992Che2, 1992Eib, 1992Hay, 1992Lu, 1992Mat, 1992Nas,
1993Ban, 1993Lee, 1993Men, 1993Nas, 1993Was, 1994Bes, 1994Fre1, 1994Fre2, 1994Law, 1994Lef,
1995Div, 1996Log, 1996Qui, 1997Div, 1997Ham, 1997Pop, 1997Ros, 1997She, 1998Dun, 1998Ma,
1999Rot, 2000Bou, 2000Dun, 2000Gre1, 2000Gre2, 2000Jon, 2000Nak, 2000Sha, 2000Ste, 2000Uch,
2001Cai, 2001Gui, 2001Guo, 2001Qia, 2002Gre, 2002Kra, 2002Sha].
Large grains with an average size of 0.2 mm were obtained by [1987Tsa2] and [1990Cal]. Further
replacement of Cu by Al in (Fe Cu Al )alloys was said to reveal a three-phase structure of (Al)+
15 20-x 65+x
FeAl +FeCu Al [1988Tsa].
3 2 7
Pseudobinary Systems and Temperature – Composition Sections
The section Al Fe-Al Cu was reported by [1928Arc] as a pseudobinary system, however, this section is not
3 2
exactly pseudobinary [1928Arc, 1990Fau2]. Some pseudobinary phase diagrams along the composition
lines of the Cu Al - Fe Cu Al , Fe Cu Al - Fe Cu Al , Fe Cu Al - Fe Cu Al and
35 65 20 15 65 1.5 30 68.5 1.5 40 58.5 3 30 67 3 40 57
Fe Cu Al - Fe Cu Al were determined by [2000Yok1, 2000Yok2], which show that the primary
5 30 65 5 40 55
crystal from the melt is the (cid:27) phase, and then (cid:45) phase is formed by a peritectic reaction. [2000Yok1 and
i
2000Yok2] only focused on the two-phase (L+(cid:45)) region, and did not give detailed information. In addition,
i
it was found that some phase equilibria do not follow the phase equilibria rules.
More recently, [2003Zha2] reported a series of vertical phase diagrams, including the pseudobinary systems
along the Fe Al -Cu Al (Fig. 1), Cu Al - Fe Cu Al (Fig. 2), Cu Al - Fe Cu Al
22.8 77.2 57.5 42.5 10 90 20 30 50 37.5 62.5 20 21 59
(Fig. 3), Fe Al - Fe Cu Al (Fig. 4) and the vertical section diagrams with 25 at.% Cu, 5 at.%
14.5 85.5 3.5 50 46.5
Fe, 7.5 at.% Fe, 10 at.% Fe, and 12 at.% Fe (Figs. 5-9). In the investigations of [2002Zha, 2003Zha2], the
phase equilibria of the (cid:45) phase and other related phases are precisely described, and the icosahedral phase
i
is formed via a peritectic reaction (L+(cid:27)+(cid:7)(cid:156)(cid:45)) at 882°C, the shrinkage of the phase field with decreasing
i
temperature gives an indication of the compositional influence on the stability of the icosahedral phase.
[1939Bra1, 1939Bra2, 1971Pre] reported the existence of slightly distorted structures of the (cid:27) phase. In
Fig.1 [2003Zha2] shows them as two phases, labeled as (cid:27) and (cid:27) , based on of the results of [1939Bra1,
1 2
1939Bra2 and 1971Pre]. However, none of the authors [1939Bra1, 1939Bra2, 1971Pre, 2003Zha1,
2003Zha2, 2003Zha3] studied these structures in details.
[2003Zha2] did not distinguish between (cid:19) and (cid:19) except for the vertical section shown in Fig. 3, where
1 2
these two phases are distinguished. This is mainly concluded from their existence in the binary Al-Cu
system and supported by a few DTA and MTA measurements. According to this section a ternary reaction
corresponding to the (cid:19) and (cid:19) transition occurs at a temperature between ~595 and 565°C, involving liquid
1 2
phase. Below this temperature only (cid:19) should exist. However, [2003Zha1, 2003Zha2, 2003Zha3] did not
2
consider this fact in the reaction scheme and in other vertical sections and used (cid:19) as notation in all figures.
Further investigations would be required to clarify phase equilibria involving different modifications of the
(cid:27) phase, as well as the (cid:19) and (cid:19) phases.
1 2
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Al–Cu–Fe 3
It should be noted that the vertical sections presented here from [2003Zha2] are not always coherent with
the accepted binary systems.
[1998Wan] presented the calculated vertical section diagrams of 5, 10, and 15 mass% Al with a
consideration of the ordered structure of the bcc phase ((cid:5)(cid:13)Fe), as shown in Figs. 10-12, which indicate that
the B2 ordered phase ((cid:7)) is not formed in the 5 mass% Al vertical sections. However, the metastable and
stable A2/B2 ordering reaction (((cid:5)(cid:13)Fe)/(cid:7)) appears in the 10 and 15 mass% Al vertical sections,
respectively; and the miscibility gap of the B2 phase ((cid:7)) also appears in 15 mass% Al vertical section.
Invariant Equilibria
Two partial reaction schemes in the Cu-rich and Al-rich corners were proposed by [1938Nis] (Fig. 13), and
[1954Phi, 2003Zha3], respectively. In the Al-rich corner [2003Zha3] presented a detailed Scheil reaction
scheme including solid state reactions, where 13 four-phase equilibria, three three-phase eutectic equilibria,
four three-phase peritectic equilibria, and two three-phase eutectoid reactions are included (Fig. 14). In the
Cu-rich portion the invariant reactions related to the (cid:7) phase are revised, as shown in Fig. 13, because
0
[1998Liu] reported that no (cid:7) phase exists at high temperature in the Al-Cu system. The reaction at 1048°C,
0
given as L+T(cid:156)((cid:11)Fe)+Cu Al by [1938Nis], where the phase T was considered to be a ternary compound, is
3
not compatible as a transition type reaction with the other equilibria, but should be a peritectic type
L+((cid:5)(cid:13)Fe)+((cid:11)Fe)(cid:156)Cu Al.
3
The invariant reactions are listed in Table 2.
Liquidus Surface
Polythermal projections of the liquidus surface are proposed in Figs. 15 and 16 for the Cu- and Al- rich
corners, respectively. Figure 17 shows combined projection of liquidus surface with tie lines of the
four-phase equilibria based on the works of [1991Leg] and [2003Zha1]. The ternary phase (cid:45) , close to (cid:45),
4 i
is omitted in these figures. A partial liquidus surface diagram in the Al-rich portion and the formation
temperature of (cid:45) phase is presented by [2000Yok1, 2000Yok2], which is in basic agreement with that
i
reported by [2003Zha1], who constructed the liquidus surface in the Al-rich portion, as shown in Fig. 16,
where 12 four-phase equilibria with the liquid phase exist.
Isothermal Sections
Figure 18 shows the Al-rich part of the isothermal section at room temperature obtained by [1991Fau] by
combining experimental results of [1990Cal] with previous literature data in the range of compositions
around the icosahedral (cid:45) phase, in which (cid:45) is not shown. Furthermore, [1992Gay1 and [1992Gay2]
i 4
determined the isothermal phase diagrams at temperatures from 550-800°C in the Al-rich region using
scanning electron microscopy and energy dispersive spectroscopy. This study indicates that the B2 ordered
phase ((cid:7)) has considerably greater solubility of Cu than previously reported, extending from AlFe to the
composition of about Fe Cu Al . A schematic section at 680°C in the vicinity of the icosahedral region
5 45 50
was determined by [1993Gra] with a combination of the results of [1992Gay1, 1939Bra1]. The results of
[1993Gra] show that at 680°C, three crystalline phases surround the icosahedral region: the monoclinic (cid:27)
phase, the ordered simple cubic ((cid:7)) phase and ordered tetragonal (cid:45) phase. [2001Ros] constructed the
2
isothermal section at 850°C. [1997Oht] has studied the solid/liquid equilibria in the Cu-Fe portion using
diffusion couple method. [1998Wan] performed the experimental determination and thermodynamic
calculation of the phase equilibria in the Cu-Fe side portion with a special attention for A2/B2 ordering
transition. There exists an order-disorder A2/B2 transition in this system, and a stable B2 phase ((cid:7)) is
formed over a wide range of compositions from the Al-Fe binary system to the Al-Cu binary system at
800-1000°C (Figs. 19-24). It is interesting to note that a miscibility gap of the bcc phase ((cid:7)) was divided
into A2+A2 (((cid:5)(cid:13)Fe)+Cu Al), A2+B2 (Cu Al+(cid:7)) and B2+B2 (((cid:7)(1)+ ((cid:7)(2)) two-phase regions. [2003Zha3]
3 3
determined isothermal sections at 800, 700, 645, 620, 617, 600, 592 and 560°C using SEM/EDS methods
together with structural investigations, as shown in Figs. 25-32, in which the (cid:45) icosahedral quasicrystalline
i
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