Another type of common and relative

Another type of common and relatively simple phase diagram found for binary alloys is shown in Figure 9.7 for the copper–silver system; this is known as a binary
eutectic phase diagram. A number of features of this phase diagram are important
and worth noting. First, three single-phase regions are found on the diagram: , ,
and liquid. The  phase is a solid solution rich in copper; it has silver as the solute
298 • Chapter 9 / Phase Diagrams
Tensile strength (MPa)
Tensile strength (ksi)
Elongation (% in 50 mm [2 in.])
400
300
200
0
(Cu)
20 40 60 80 100
(Ni)
Composition (wt% Ni) Composition (wt% Ni)
(a) (b)
60
50
40
30
60
50
40
30
20
0
(Cu)
20 40 60 80 100
(Ni)
Figure 9.6 For the copper–nickel system, (a) tensile strength versus composition, and
(b) ductility (%EL) versus composition at room temperature. A solid solution exists over
all compositions for this system.


+ L


+ L
 + 
B
C
E
F
H
G
Liquidus
Liquid
Solvus
Solidus

8.0
(C E) 
91.2
(C E)
71.9
(CE)
Temperature (°C)
(Cu) Composition (wt% Ag) (Ag)
Composition (at% Ag)
Temperature (°F)
1200
A
0 20 40 60 80 100
2200
2000
1800
1600
1400
1200
1000
800
600
400
800
600
400
1000
200
0 20 40 60 80 100
779°C (TE)
Figure 9.7 The copper–silver phase diagram. [Adapted from Binary Alloy Phase
Diagrams, 2nd edition, Vol. 1, T. B. Massalski (Editor-in-Chief), 1990. Reprinted by
permission of ASM International, Materials Park, OH.]
JWCL187_ch09_281-341.qxd 9/18/09 11:54 AM Page 298
component and an FCC crystal structure. The -phase solid solution also has an
FCC structure, but copper is the solute. Pure copper and pure silver are also considered to be  and  phases, respectively.
Thus, the solubility in each of these solid phases is limited, in that at any temperature below line BEG only a limited concentration of silver will dissolve in copper (for the  phase), and similarly for copper in silver (for the  phase). The
solubility limit for the  phase corresponds to the boundary line, labeled CBA, between the /(  ) and /(  L) phase regions; it increases with temperature to
a maximum [8.0 wt% Ag at 779C (1434F)] at point B, and decreases back to zero
at the melting temperature of pure copper, point A [1085C (1985F)]. At temperatures below 779C (1434F), the solid solubility limit line separating the  and 
  phase regions is termed a solvus line; the boundary AB between the  and 
 L fields is the solidus line, as indicated in Figure 9.7. For the  phase, both solvus
and solidus lines also exist, HG and GF, respectively, as shown. The maximum solubility of copper in the  phase, point G (8.8 wt% Cu), also occurs at 779C (1434F).
This horizontal line BEG, which is parallel to the composition axis and extends between these maximum solubility positions, may also be considered a solidus line; it
represents the lowest temperature at which a liquid phase may exist for any copper–silver alloy that is at equilibrium.
There are also three two-phase regions found for the copper–silver system (Figure 9.7):   L,   L, and   . The - and -phase solid solutions coexist for
all compositions and temperatures within the    phase field; the   liquid and
  liquid phases also coexist in their respective phase regions. Furthermore, compositions and relative amounts for the phases may be determined using tie lines
and the lever rule as outlined previously.
As silver is added to copper, the temperature at which the alloys become totally
liquid decreases along the liquidus line, line AE; thus, the melting temperature of copper is lowered by silver additions. The same may be said for silver: the introduction of
copper reduces the temperature of complete melting along the other liquidus line, FE.
These liquidus lines meet at the point E on the phase diagram, through which also
passes the horizontal isotherm line BEG. Point E is called an invariant point, which is
designated by the composition CE and temperature TE; for the copper–silver system,
the values of C
E and TE are 71.9 wt% Ag and 779C (1434F), respectively.
An important reaction occurs for an alloy of composition CE as it changes temperature in passing through TE; this reaction may be written as follows:
(9.8)
Or, upon cooling, a liquid phase is transformed into the two solid  and  phases
at the temperature TE; the opposite reaction occurs upon he

Kết quả (Anh) 1:

Another type of common and relatively simple phase diagram found for binary alloys is shown in Figure 9.7 for the copper-silver system; This is known as a binaryeutectic phase diagram. A number of features of this phase diagram are importantand worth noting. First, three-single phase regions are found on the diagram:,,and liquid. The phase is a solid solution rich in copper; It has silver as the solute298 • Chapter 9/Phase DiagramsTensile strength (MPa)Tensile strength (ksi)Elongation (% in 50 mm [2 inches])4003002000(Cu)20 40 60 80 100(Ni)Composition (wt% Ni) Composition (wt% Ni)(a) (b)6050403060504030200(Cu)20 40 60 80 100(Ni)Figure 9.6 For the copper-nickel system, (a) tensile strength versus composition, and(b) ductility (% EL) versus composition at room temperature. A solid solution exists overall compositions for this system.+ L+ L + BCEFHGLiquidusLiquidSolvusSolidus8.0(C E)91.2(C E)71.9(CE)Temperature (° C)(Cu) Composition (wt% Ag) (Ag)Composition (at% Ag)Temperature (° F)1200A0 20 40 60 80 100220020001800160014001200100080060040080060040010002000 20 40 60 80 100780° C (TE)Figure 9.7 The copper-silver phase diagram. [Adapted from Binary Alloy PhaseDiagrams, 2nd edition, vol. 1, t. b. Massalski (Editor-in-Chief), 1990. Reprinted bypermission of ASM International, Materials Park, OH.]JWCL187_ch09_281-341. qxd 9/18/09 11:54 AM Page 298component and an FCC crystal structure. The-phase solid solution also has anFCC structure, but copper is the solute. Pure copper and pure silver are also considered to be and phases, respectively.Thus, the solubility in each of these solid phases is limited, in that at any temperature below line BEG only a limited concentration hand of silver will dissolve in copper (for the phase), and similarly for copper in silver (for the phase). Thesolubility limit for the phase corresponds to the boundary line, labeled CBA, between the/() and/(L) phase regions; It increases with temperature toa maximum [wt% at 779 Ag 8.0 C (1434 F)] at point B, and decreases back to zeroat the melting temperature of pure copper, point A [1085 C (1985)]. At temperatures below C 779 (1434 F), the solid solubility limit line separating the andphase regions is termed a solvus line; the boundary between the AB andl fields is the solidus line, as indicated in Figure 9.7. For the phase, both solvusand solidus lines also exist, HG and GF, respectively, as shown. The maximum solubility of copper in the phase, point G (8.8 wt% Cu), also occurs at the C 779 (1434 F).This horizontal line BEG, which is parallel to the axis composition and extends between these maximum solubility positions, may also be considered a solidus line; Itrepresents the lowest temperature at which a liquid phase may exist for any copper-silver alloy that is at equilibrium.There are also three two-phase regions found for the copper-silver system (Figure 9.7): L, L, and. The-and-phase solid solutions coexist forall compositions and temperatures within the phase field; the liquid andliquid phases also coexist in their respective phase regions. Furthermore, compositions and relative equivalent for the phases may be determined using the tie linesand the lever rule as outlined previously.As silver is added to copper, the temperature at which the alloys become totallyliquid decreases along the liquidus line, line AE; Thus, the melting temperature of copper is lowered by silver additions. The same may be said for silver: the introduction ofcopper reduces the temperature of complete melting along the other liquidus line, FE.These liquidus lines meet at the point E on the phase diagram, through which alsopasses the horizontal isotherm line BEG. Point E is called an being invariant point, which isdesignated by the CE composition and temperature TE; for the copper-silver system,the values of CE and TE are wt 71.9% Ag and C 779 (1434 F), respectively.An important reaction occurs for an alloy of composition CE as it changes temperature in passing through TE; This reaction may be written as follows:(9.8)Or, upon cooling, a liquid phase is transformed into the two solid and phasesat the temperature TE; the opposite reaction occurs upon the he

Kết quả (Anh) 2:

Another common type of phase diagram and Relatively simple for binary alloys found Shown in Figure 9.7 is for the copper-silver system; this is known as a binary
eutectic phase diagram. A number of features of this phase diagram are Important
and worth noting. First, single-phase three are found on the diagram vùng:?,?,
And liquid. The? rich phase is a solid solution in copper; it has silver as the solute
298 • Chapter 9 / Phase Diagrams
Tensile strength (MPa)
Tensile strength (KSI)
Elongation (% in 50 mm [2 in.])
400
300
200
0
(Cu)
20 40 60 80 100
(Ni)
Composition (wt% Ni) Composition (wt% Ni)
(a) (b)
60
50
40
30
60
50
40
30
20
0
(Cu)
20 40 60 80 100
(Ni)
Figure 9.6 copper-nickel For the system, (a ) tensile strength versus composition, and
(b) ductility (% EL) at room temperature versus composition. A solid solution exists over
all compositions for this system.
?
?
+ L
?
?
+ L
? +?
B
C
E
F
H
G
Liquidus
Liquid
Solvus
solidus
?
8.0
(CE)?
91.2
(CE)
71.9
(CE)
Temperature (° C)
(Cu) Composition (wt% Ag) (Ag)
Composition (at% Ag)
Temperature (° F)
1200
A
0 20 40 60 80 100
2200
2000
1800
1600
1400
1200
1000
800
600
400
800
600
400
1 000
200
0 20 40 60 80 100
779 ° C (TE)
Figure 9.7 The copper-silver phase diagram. [Adapted from Binary Alloy Phase
Diagrams, 2nd edition, Vol. 1, TB Massalski (Editor-in-Chief), 1990. Reprinted by
permission of ASM International, Materials Park, OH.]
18/9/09 11:54 AM Page 298 JWCL187_ch09_281-341.qxd
component and an FCC crystal structure. The? -phase Cũng solid solution has an
FCC structure, but copper is the solute. Pure copper and pure silver cũng Considered to be? and? phases, respectively.
thì, the Solubility in each of những solid phases is limited, at any temperature below actual print only a limited line BEG sẽ concentration of silver in copper dissolve (for the? phase), and similarly for copper in silver (for the? phase). The
Solubility limit for the? phase corresponds to the boundary line, labeled CBA, the between the? / (???) and? / (?? L) phase vùng; it increases with temperature to
a maximum [8.0 wt% Ag at 779? C (1434? F)] at point B, and decreases back to zero
at the melting temperature of pure copper, point A [1085? C (1985? F) ]. At temperatures below 779? C (1434? F), the solid Solubility phân cách cách the limit line? and?
? ? vùng phase is termed a solvus line; the boundary AB giữa? and?
? L fields is the solidus line, as indicated in Figure 9.7. For the? phase, both Show solvus
and solidus lines cũng exist, HG and GF, respectively, as Shown. The maximum Solubility of copper in the? phase, point G (8.8 wt% Cu), cũng Occurs at 779? C (1434? F).
This line BEG horizontal, parallel to the composition mà axis and extends maximum giữa Solubility những positions, unfortunately cũng be Considered a solidus line ; it
đó là the lowest temperature a liquid phase at sewing exist for any copper-silver alloy nằm at equilibrium.
There are three two-phase cũng vùng copper-silver found for the system (Figure 9.7):? ? L,? ? L, and? ? ?. The? - And? -phase Solid solutions coexist for
all compositions and temperatures trong? ? ? phase field; the? ? liquid and
? ? liquid phases coexist cũng vùng trong respective phase. Furthermore, compositions and relative phases lẽ tiền định for the tie lines using
the lever rule as outlined and trước.
As silver is added to copper, the temperature at đó alloys trở totally
liquid decreases along the Liquidus line, line AE; thì, the melting temperature of copper is lowered by silver additions. The same unfortunately be said for silver: the introduction of
copper reduces the melting temperature of complete line along the other Liquidus, FE.
These lines meet at the point Liquidus on the phase diagram E, through mà am also
passes the horizontal line BEG isotherm. Point E is an invariant point gọi, mà
CE designated by the composition and temperature TE; copper-silver for the system,
the values of C
E and 71.9 wt% Ag are TE and 779? C (1434? F), respectively.
An Important reaction for an alloy of composition Occurs CE as it changes temperature in passing through TE; this reaction as follows lẽ ghi:
(9.8)
Or, upon cooling, a liquid phase is Transformed Into the two solid? and? phases
at the temperature TE; Occurs upon the opposite reaction he