nase diagrams:
Introduction
Phase Diagrams
Introduction
Cu-NiAlloy (Cu-NiSystem)
Cu (CCP) T= l085°C
Ni (CCP
TN= 1453C
Ni C1453°c)
Trm
Liguidus
lia
T
K
12c
S cCPND
(Subs+iwAom Solid
Solution of Cu & Ni
CcCP
C
NIPPEL
7C°5*lo83)/2
w t Ni?
Combositian
Ni
TSC, 1IT OLHI,
E Phase diagrams: Introduction
Equil ibrium Phase Diaqram
Equil ibrium Diagram
Phase Diagram
A diagram in the space of relevamt
thermodynamic vaniables Ceg. temperature
and composition)
equilibrium
22:17/22:35
in dicatin9 bhases in
is called
a
PHASE DIAGRAM,
E Phases and componentsS
Phases
NPREL
I
0:07/14:35
Combonents
Phase: A chemically homoqeneovs,
physically distinct and
mechanically sebanabe bant of
a system is called a
phase
Three phases of matter
Ligvid, Solid, Gas.
Solid Phases: Differmnt crystal Structru
will be considesed difforhnt phasu.
Fe
BCC ( ) ,
CCP (T)
TSC, IT DLH!
EPhases and components
Combonent The Indefpendent chemical speies
which he
Celement, Combound) n terms
Combosi tion
e
a
system
is
specifed
called Cómponénts.
In
Cu-Ni
I
7:48/14:36
NPEL
of
ane Cua
System:Componenhamd
N
is
i
Some 6xamples
System
Phasess
Combonenfs
liqvid
hlater
Water +ice
Brine
Mild Stee
iquid +Jolid
HO
NaCl+ HO
Fe,
igvld Soluton
C
Gibbs Phase Rule: relation
of no. componeni, no.
deqrees
freedorn.
haase
and
ETSC, UT D
E Phases and components
Tybes of Phase Diagrams
Based
numberr of Combonens
on
Unary Diagram
Single Combonent
Ginary
Diagram
Two Combonents
Ternany Diagram
Three Combonents
E Uses of phase diagrams
Three vestions
That
can
be ansarered usin9
Phase Diagram
ConstitutionPoint
Ten
Cu-Ni Binary Diagramn
Combesio
1500
1453 A þolnt(«T)
On the
1400
bha se
Solidus
L+
1300
1200
Liquidus
Liquidus
A
C0tN
1200
1400
2p
ComposiHon
Xhald in
Cquilbrium
af temp.T.
1085
1000
diagran
represents
an aley of
Compositton
w t f Ni
Ni
ETSC, IT DELHI
5 Uses of phase diagrams
The 7hree Questions
Sor any
consihution
point cx, Tphase diagram
can be vsed to anSwien 3
Q1 bat
ore
the
guesions
phases bresent ?
2 : What ane he combositions of the phases ?
Q3
NPTEL I
What
ans
the relative amounh
of
the
phaser?
ETSC JIT DELHL
8:36/8:59
E Phases presentin thesystemn
Phasel Diagramns
What
at
a
are the
bhases bresent
iven constitutian boint
T)?
Comp
Tevop
ETSC IUT OELHI
K
PE
0:35/9:55
Phasees present at a qiven constitution
paint Cx, T
Binan"Cu-Ni Diagram
A:co wt
400
1200c
L
Phase: -phase.
B 50a t N i
1300
1200
A
1250C
Phase
4400
4000
u Cu 20
PTE
Ne
60
wtNi
o
N
+
Tan phases.
ETSC, I T DTLHI
The 1-2-1 Rule
fremove
horizontelly
1500
Clsotherm)
L
rom one
ingle phare
a
1300
anothn single
hane (eq.o «)
t200
m
we will
alays hare q
2-6haa LtR
1100
1000C
1PTE
to
20
40 N Go
wt Ni
to
Ni
region in
bénween.
ETSC, UT DELHI
Phase Diaqrams
Q2
What are
combositions oF
the
the bhases
?
breseht
EComposition of phases present inthe system
Combosition
fracton. cr f
kctA,
differant components
wt fract#on
atom
Co
atom fracien
alloy combositon
Cfrachon of combonens in he whole
alloy
phase
I
3:54/12:40
þhase CombosiHon
fraction of compannG in aginen
hase)
ETSG, IT DELHI
Combosition for
the constitution Pbint A
Co
A
1500
o
t
Ni
4150
1400
Phase:
C
1300
Co
1200
For single phase
A
Phase Combosito
1100
)
1000
O
C
8 0 wty Ni
Alloy
CompesiHen
20
80
60
- w t / Ni+
Ni
ETSC, 1IT DELHI
Combosition of phases in the 2-bhase region
s o wNTie-Line Rule
T: 300°c
L
Phases
400
1300
Tie Lne
Solidus
An isohe rm
in the 2-bhase
C
.looo
TEL.
Ca CL ?1
Liquidu
200
Lt
Ca
reglon rünnin9
om one boun
dany to the otte
50
20
wt
NN
Ni
ETSC, IT DELHI
"ie Line:Calculating Composition and Fraction of Phases
IQU
/ENPEReTURE
|1453'c
IQotOUS
SoLIDUS
Ly
S
t,
085
407, N
2
Cu
N:
CONOsIflON
20/.N
9:41/11:32
Ni
F
"ie Line:Calculating Composition and Fraction of Phases
LEnNG TH OF THE TiE L/NE
FRoM THE OVERALL CoM Po S/T/
RACTIO
To THE
Of ONE PHASE
9:47/11:32
OTHER PAASE BOUNDARY
ToTAL LEN4 TH of TIE
LI'NE
Proportion of phases presentin the system
Phase Diagrams
Q3:
What ane the relaHie amounts
or
probortion of phatds present ?
Proportion of phases present in thesystem
Relative Amounts of Pha:es
f
Single Phare Reqion
500
L
145a'c
properken
in the
whoie alio;
400
proporHon
aa combo
30o
hent in he
hare .
1200
A
Lt
P
1100
1085
wt
C.
20
wtyNi
Ni
Ni
T: I5o'C
phae
1o00
8/13:4
Co
o
:G
10)
Rela tiv Amoun+
14400
of Tio Phasgs Region
40 wt N'
o
o
L 64
L
O.64
CL 2 2
f - = O36
C
300
50
ILEveR RULe
or relatir
200
rgbortons.
total anm
22
I000
20
Ca
40 50 6o
wty N
80
Ni
PR
40-22
So-222
5Microstructure evolution during solidificationinisomorphous systems
Microstructure Evolutiorn
Clurin9 soliclifica tion
1soMOR PHOUs SrstEM)
-ETSC¢+#TDELH
C
NPTEL
0:21/16:06
Microstructure evolution during solidification in isomorphous systems
An
IsoMORPHOUSs PHASE DIAGRAM
Solidificawon
1500
L
L
Dins3/
G 0 wt Ni
40 w t Cu
1453
1400
500
1300-
CL
Solidificw
1200
L+
Compe
4400
1O85
-q
Singe
kAase
dys talpoe
1000
20
Cu
-
15:58/16:06
grin
60
wt f Ni
s
9ran
CNi)
bound
-y
ectic
System
Eutectic system
Pb-Sn Solder Alloy
Soldering:
Low
Need
melting alloy
Strength
CAlloy Stronger
han pure ele mems)
Pb
Sn
D3:08/16:45
e
T .Sn
327 °c
232°c
Eutectic system
(
Pb-Sn Phase Diaqram
327
liguichs
300
200t Solids
p232
20
CPb)
-
D8:55/16:45
wt/ S
(Sn)
TSG 7
D
Pb-Sn
A
System
Eutectie System
Easy melHnn9
400
32
300
20
Bounadanies
&utectc Alloy
20. LiLquidvs
83
SutecR o 2
TAP Pb
%
wt
L/L+d
Liquidvs
EUTECTIC
20
Liguidus +
L
HONzON
TAL
232
Soli
des
Solidus
+L
Solvus
/d+p
(Eutechc Hortevn
Sn
ta
EutecHe combasitm..
utectic reaction
fectic Keaction
0:05/9:32
ETSC, T
DELH
INVARIANT ReCaCTONi EutecHc Reacion
T483
(G2) Coo
327
oL
/
Pb
wty. Snn
EutecHG
232
Sn
(18)
mixture
Eutecic mirtwre
or
Eutechc micro consihuenk
IL
Eutectic, Hypoeutectic
6
Hypereutectic Alloys
E Eutectic, hypoeutectic and hypereutectic alloys
Eutecic Alloy
Pb-Sn Phase Diaqram
400
40
327
300
Eutecic
Lt
200f
183
/
-Hyp9
eute hc
ec
alloy
o
Eutectic mixtue
232
Cmicro cons Hiiest
tvent)
Hyper
eutecHe
aoy
20
Pb
K NPEL C
Polnt
D6:57 /27:42
w t Sn
E62
Sn
TBCTIT DELH
400
Phases n
300
2200
Lt
TE33c
I00
bypoeutectic alloy
GL
Ce
2
a
ot Sn.
Just above TE
20
(40)
80
Sn
w t Sn
Pb
Microstructure evoluthon in
bypoeutectic alloy poeutecHC
o
eutecHe mixturr
1ierocemsikmms
a
S
Just below TE
hypoeutectie alloy
IIT DELHI
Microconstituents in
a
bypeeutechc alley
- þmeute
He
327
Gutectic
183
mixtuna.
62
18
To deter mine the
microconstituens
we dra w h e He
hne in h e
tw-pkaw
P%
c t Sn
region just above he eutechie ttms T
T
roeutectie o vst jus* above Ts = G2-
G2-1
Jutectie metune =
I-o5
o S
22 os
ETSC, T
DELH
Phasos in a
Hybocutechc Alley
To deternine total
and fotal In
L
32
232
the alloy we draw
h e He-line
just below T
40
Taotal
Tstal
ftoto p
gutecHc
q7 4 o
57 : O72
97-18
I-o:*2
total
O
2
&&
Tproeuecte
O72-O
5
O 22
S
eutecHC
ee
YSC, iIT L H I
EGibbs' phaserule
JIBBS
O:06/31:44
PHASE ULE
E Gibbs'phaserule
GbbS Phase Rule
P
No. of Phases in equilibrium
C
No.
of components
F= Degrees of Freedom
NPEL
1:48/31:44
CiBs
phase rule
Thermodyna mic
Vaniables
for
Gibbs Phase
Rule
Pressure and Temperqure Cif both are vnniable)
If Pressure is fxed, hen nly temp is vasiable
Combosiion vaniables
Only phase combositions
ans
considered
asvoiables
Overall
alloy composition
vaiable,except hen
e
is
is nat
have
a
a
aloy
Single phase equilibrium when aloy
Combosiion saso he phase combosi on.
TsCIT
ORLH
6:23/31:44
No.
If
to
f
Combositon vaniables.
thene
ane
specify
C
C-
combonents
then
combositons for
needs
Comboaition vaniables.
for
P
Total no. d
V=
phases
one
one
need
phase.
each
PC-1)
vaiables
PCC-1) 2
iF ossvre amod
emta ani vaniables.
V
=
PCC-1) + 1
P is cmstamt
only
f
ETSC, IT DELHI
Degrees of Freedom:
F: No.
of hermody namic vaniables which
be
without
can
speiKed indebendently
changing the hases ik equilibrium.
Since there is ther
mo
ctynamic equilibrium,
ae equilib riu m rela hions
thermody da mic vaniables. F
bervem me
automahicall ixed by
by
eguilibrum
here
certain no. d
neations.
speci
vaniables, otens ars
hese
ETSC, 1IT DELHI
GIBes PHASE RuLE
F
F
=
C-P
2
C-P
+1
both pressure
if
temberatwre ane
onl
and
vannbles
tempemene is
vaniabte Fixed Areure)
for binan bhase diaqamg
consideud by bs.
aressure 1 am)
Applicabte
b
Cxample of Abplication f
Gibbs Phase Rule
Rule
L
(4) Singte Phase L in
Pru
equi librlumD
Lt
CLT
F=C-P +1
+
Pb
2-
w t Sn.
(2) Tho bhase
GL
V2
L+
In equilibrium
V=3
C - P+ I =
T
L
TE
Pb
w t Sn.
Sn
Three Phase
eguilibrium L , {
CL C CpT (V= 4)
P=3,
F
C-P+|
2 -3 +I = o
T
Horizontal Line
Inraniant
phase reacton
L
oktB
Pb
Three
w
Sn
Phase eguilibrium
Sa p
C-P+l E
P-3,
F
Sn
L *, B
L,
(v= 4i)
2-3+|:O
ETSC, T
DEL
S+L - S
L - S+S
S - S+S
Peritectoid S+S - S
alpha