material science

1. PHASE DIAGRAM
(IRON-IRON CARBIDE)
(Part – 3/3)
Prepared by
VISHAL MEHTA
Reference : Material Science and Engineering,
An Introduction by William D. Callister, Jr

2. CONTENTS
Iron-Iron Carbide System Eutectoid Reaction
Iron-rich portion Iron Carbide/Cementite
Commercially Pure Iron Pearlite
Steel Coarse & Fine Pearlite
Hypoeutectoid Steel Proeutectoid Ferrite
Hypereutectoid Steel Proeutectoid Cementite
Cast Iron Bainite
Hypoeutectic Cast Iron Martensite
Hypereutectic Cast Iron BCT Structure
Alpha-iron/Ferrite Tampered Martensite
Polymorphic Transformation Eutectic Reaction
Gamma-iron/Austenite Ledeburite
Delta-iron/Ferrite Peritectic Reaction
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 2

3. IRON-IRON CARBIDE PHASE DIAGRAM
•In this topic, detail of Iron-Iron Carbide
diagram will be discussed with various
terms, phases generated &
transformation occurred.
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 3
Fe Fe3C

4. • IRON-IRON CARBIDE system may be
divided into two parts
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 4
0 wt% C
100 wt% Fe
100 wt% C
0 wt% Fe
6.70 wt% C
93.30 wt% Fe
Iron-rich portion Carbon-rich portion
Pure
Iron
Pure
Graphite
or
Carbon

5. • Iron-rich portion may be divided into
three parts
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 5
0 wt% C
100 wt% Fe
6.70 wt% C
93.30 wt% Fe
2.14 wt% C
97.86 wt% Fe
Steel Cast Iron
0.008 wt% C
99.992 wt% Fe
Commercially
Pure Iron

6. • Steel may be divided into two parts
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 6
0.76 wt% C
99.24 wt% Fe
Hypoeutectoid
Steel
Hypereutectoid
Steel
0.008 wt% C
99.992 wt% Fe
2.14 wt% C
97.86 wt% Fe
Eutectoid
Steel
Less than eutectoid More than eutectoid

7. • Cast Iron may be divided into two parts
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 7
Hypoeutectic
Cast Iron
Hypereutectic
Cast Iron
2.14 wt% C
97.86 wt% Fe
Eutectic
Cast Iron
Less than eutectic More than eutectic
6.70 wt% C
93.30 wt% Fe
4.30 wt% C
95.70 wt% Fe

8. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 8
At room
temperature
stable form of
pure iron is
present called,
FERRITE.
Ferrite is also
called as
-iron.
It has BCC
Structure.
Temperature is
below 912OC

9. Ferrite or -iron or -ferrite
• Interstitial solid solution of Carbon in BCC iron (Fe).
• Stable form of iron at room temperature to 912OC.
• The maximum solubility of Carbon is 0.022 wt% at 727OC
• Transforms to FCC γ-austenite phase at 912OC.
• It dissolves only 0.008 % C at room temperature
• Ductile
• Highly magnetic
• It has a low tensile strength of approximately 2800 Kg/cm2
• It is soft phase.
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 9

10. POLYMORPHIC TRANSFORMATION
•It is a transformation in which a component
changes its crystal structure.
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 10

11. POLYMORPHIC TRANSFORMATION
•It is a transformation in which a component
changes its crystal structure.
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 11
Type 1 component/metal
Type 1 crystal structure

12. POLYMORPHIC TRANSFORMATION
•It is a transformation in which a component
changes its crystal structure.
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 12
Type 1 component/metal
Type 1 crystal structure
Polymorphic
Transformation

13. POLYMORPHIC TRANSFORMATION
•It is a transformation in which a component
changes its crystal structure.
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 13
Type 1 component/metal
Type 1 crystal structure
Polymorphic
Transformation
Type 1 component/metal
(same component/metal)
Type 2 crystal structure

14. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 14
At 912OC Ferrite
experiences
polymorphic
transformation to
AUSTENITE.
Austenite is also
called as
γ-iron.
It has FCC
Structure.
Temperature is
between
912OC to 1394OC

15. Austenite or γ-iron or γ-austenite
• Interstitial solid solution of Carbon in FCC Fe.
• The maximum solubility of Carbon is 2.14 wt % at 1147°C .
• Transforms to BCC δ-ferrite at 1395 °C.
• Is not stable below the eutectic temperature (727 ° C) unless cooled rapidly.
• It is stable above 727°C .
• This phase plays an important role in the phase transformations of steels.
• High formability, most of heat treatments begin with this single phase.
• It is normally not stable at room temperature. But, under certain
conditions, it is possible to obtain austenite at room temperature
• It is generally soft
• Ductile
• Non- magnetic
• It is denser than ferrite.
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 15

16. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 16
At 1394OC
austenite
experiences
polymorphic
transformation to
FERRITE.
It is also called as
-iron.
It has BCC
Structure.
Temperature is
between
1394OC to 1538OC

17. Ferrite or -iron or -ferrite
•Interstitial solid solution of Carbon in BCC Fe
•The same structure as -ferrite.
•Stable only at high Temperature , above 1395 °C.
•Melts at 1539 °C.
•Maximum carbon solubility: 0.09-0.10 wt.%.
•BCC structure
•Paramagnetic
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 17

18. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 18
0OC
912OC
Ferrite -iron BCC

19. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 19
0OC
912OC
1394OC
Austenite γ-iron FCC
Ferrite -iron BCC

20. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 20
0OC
912OC
1394OC
1538OC
Ferrite -iron BCC
Austenite γ-iron FCC
Ferrite -iron BCC

21. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 21
0OC
912OC
1394OC
1538OC
Above 1538OC Liquid phase
Ferrite -iron BCC
Austenite γ-iron FCC
Ferrite -iron BCC

22. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 22
0OC
912OC
1394OC
1538OC
Above 1538OC Liquid phase
Ferrite -iron BCC
Austenite γ-iron FCC
Ferrite -iron BCC
The -ferrite
is virtually
the same as
-ferrite,
except for the
range of
temperatures
over which
each exists.

23. EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 23
• Recall….
• What is eutectoid reaction ?

24. EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 24
• Recall….
• What is eutectoid reaction ?
EUTECTOID REACTION
Type-1 solid phase
Type-2
solid phase
Type-3
solid phase

25. EUTECTOID REACTION
FOR
IRON-IRON CARBIDE
SYSTEM
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 25

26. EUTECTOID REACTION
FOR
IRON-IRON CARBIDE
SYSTEM
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 26
Eutectoid
Reaction
is at
727OC
and
0.76 wt% C

27. EUTECTOID REACTION
FOR
IRON-IRON CARBIDE
SYSTEM
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 27
Eutectoid
Reaction
is at
727OC
and
0.76 wt% C

28. EUTECTOID REACTION
FOR
IRON-IRON CARBIDE
SYSTEM
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 28
Eutectoid
Reaction
is at
727OC
and
0.76 wt% C

29. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 29
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
Austenite Ferrite Iron Carbide
or
Cementite
• Cementite is the hardest structure appears on
diagram.
• Crystal structure of cementite is Orthorhombic
• Cementite has low tensile strength but high
compressive strength.

30. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 30
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
Schematic representations of
the microstructures for an
iron–carbon alloy of eutectoid
composition (0.76 wt% C)
above and below the
eutectoid temperature.

31. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 31
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
The microstructure for this
eutectoid steel that is slowly
cooled through the eutectoid
temperature consists of
alternating layers or lamellae
of the two phases ( and
Fe3C) that form
simultaneously during the
transformation.

32. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 32
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
This microstructure is called
pearlite.

33. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 33
EUTECTOID REACTION FOR
IRON-IRON CARBIDE
SYSTEM
Schematic
representation
of the formation
of pearlite from
austenite;
direction of
carbon
diffusion
indicated by
arrows.

34. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 34
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
Pearlite has properties
intermediate between the
soft, ductile ferrite and the
hard, brittle cementite.

35. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 35
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
COARSE PEARLITE
• At temperatures just below the eutectoid, relatively thick
layers of both the -ferrite and Fe3C phases are produced; this
microstructure is called coarse pearlite
FINE PEARLITE
• The thin-layered structure produced in the vicinity of 540OC is
termed fine pearlite

36. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 36
Coarse
Pearlite
Fine
Pearlite

37. HYPOEUTECTOID COMPOSITION
(Hypoeutectoid steel)
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 37
Schematic representations of the
microstructures for an iron–
carbon alloy of hypoeutectoid
composition (containing less
than 0.76 wt% C) as it is cooled
from within the austenite phase
region to below the eutectoid
temperature.

38. HYPOEUTECTOID COMPOSITION
(Hypoeutectoid steel)
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 38
In fourth figure of
microstructure, proeutectoid
ferrite/ means it is already
formed in previous upper phase
(above eutectoid temperature) &
eutectoid ferrite/ means newly
formed which is part of pearlite.
(Proeutectoid means pre- or before eutectoid)

39. HYPOEUTECTOID
COMPOSITION
(Hypoeutectoid
steel)
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 39

40. HYPEREUTECTOID COMPOSITION
(Hypereutectoid steel)
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 40
Schematic representations of the
microstructures for an iron–
carbon alloy of hypereutectoid
composition C1 (containing
between 0.76 and 2.14 wt% C),
as it is cooled from within the
austenite phase region to below
the eutectoid temperature.

41. HYPEREUTECTOID COMPOSITION
(Hypereutectoid steel)
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 41
In fourth figure of
microstructure, proeutectoid
cementite/Fe3C means it is
already formed in previous
upper phase (above eutectoid
temperature) & eutectoid
cementite/Fe3C means newly
formed which is part of pearlite.
(Proeutectoid means pre- or before eutectoid)

42. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 42
HYPEREUTECTOID
COMPOSITION
(Hypereutectoid steel)

43. EXAMPLE PROBLEM
For a 99.65 wt% Fe–0.35 wt% C alloy at a temperature
just below the eutectoid, determine the following:
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 43
(a) The fractions of total ferrite and cementite phases
(b) The fractions of the
proeutectoid ferrite and pearlite
(c) The fraction of eutectoid ferrite

44. (a) The fractions of total ferrite
and cementite phases
•Assume the given point in
question is “ f ” indicated in
figure below eutectoid.
•Here to find fraction we
have to apply “Lever Rule”
for the given point.
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 44

45. LEVER RULE or
THE INVERSE LEVER RULE
• After solving Eq.1 & Eq.2
𝑾𝑳 =
𝑪𝜶 − 𝑪𝟎
𝑪𝜶 − 𝑪𝑳
=
𝑺
𝑹 + 𝑺
𝑾𝜶 =
𝑪𝟎 − 𝑪𝑳
𝑪𝜶 − 𝑪𝑳
=
𝑹
𝑹 + 𝑺
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 45
Expression of lever rule
(For this particular situation of binary isomorphous system)

46. (a) The fractions of total ferrite and cementite phases
•Here we apply
lever rule for
our problem.
•So,
•𝑾𝜶 =
𝑿
𝑻+𝑿
•𝑾𝜶 =
𝟔.𝟕𝟎−𝟎.𝟑𝟓
𝟔.𝟕𝟎−𝟎.𝟎𝟐𝟐
•𝑾𝜶 = 0.95
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 46
0.35

47. (a) The fractions of total ferrite and cementite phases
•And
•𝑾𝑭𝒆𝟑𝑪 =
𝑻
𝑻+𝑿
•𝑾𝑭𝒆𝟑𝑪 =
𝟎.𝟑𝟓−𝟎.𝟎𝟐𝟐
𝟔.𝟕𝟎−𝟎.𝟎𝟐𝟐
•𝑾𝑭𝒆𝟑𝑪 = 0.05
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 47
0.35
“OR”
one can use the relation
𝑾𝜶 + 𝑾𝑭𝒆𝟑𝑪 = 𝟏

48. (b) The fractions of the proeutectoid ferrite and pearlite
• Now for question (b) the
composition range is
changed & is up to
eutectoid reaction.
• So,
• 𝑾𝒑 =
𝑻
𝑻+𝑼
• 𝑾𝒑 =
𝟎.𝟑𝟓−𝟎.𝟎𝟐𝟐
𝟎.𝟕𝟔−𝟎.𝟎𝟐𝟐
• 𝑾𝒑 = 0.44
• (fraction of pearlite)
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 48

49. (b) The fractions of the proeutectoid ferrite and pearlite
• And,
• 𝑾𝜶′ =
𝑼
𝑻+𝑼
• 𝑾𝜶′ =
𝟎.𝟕𝟔−𝟎.𝟑𝟓
𝟎.𝟕𝟔−𝟎.𝟎𝟐𝟐
• 𝑾𝜶′ = 0.56
• (fraction of
proeutectoid ferrite)
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 49
“OR”
one can use the relation
𝑾𝜶′ + 𝑾𝒑 = 𝟏

50. • All ferrite is either as proeutectoid or eutectoid (in the pearlite).
Therefore, the sum of these two ferrite fractions will equal the
fraction of total ferrite; that is,
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 50
(c) The fraction of eutectoid ferrite
𝑾𝜶′ + 𝑾𝜶𝒆 = 𝑾𝜶
Fraction of
Proeutectoid
ferrite
Fraction of
Eutectoid
ferrite
Fraction of
Total
ferrite
𝑾𝜶𝒆 = 𝑾𝜶 − 𝑾𝜶′
𝑾𝜶𝒆 = 0.95 − 0.56
𝑾𝜶𝒆 = 0.39

51. • Now again recall
the concept of formation of Pearlite
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 51
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
• The microstructure for eutectoid steel
that is slowly cooled through the
eutectoid temperature consists of
alternating layers or lamellae of the two
phases ( and Fe3C) that form
simultaneously during the
transformation.
• This microstructure is called pearlite.

52. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 52
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
• So basically,
γ austenite ferrite + Fe3C cementite
Slow
cooling
Pearlite

53. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 53
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
• So basically,
γ austenite ferrite + Fe3C cementite
Slow
cooling
What happen, if
cooling rate is not
slow ?
Pearlite

54. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 54
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM

55. • Moderate Cooling….
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 55
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
γ austenite ferrite + Fe3C cementite
Moderate
cooling
Bainite

56. Bainite forms as
needles or plates,
depending on the
temperature of the
transformation; the
microstructural details
of bainite are so fine
that their resolution is
possible only using
electron microscopy
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 56
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM

57. Bainite forms as
needles or plates,
depending on the
temperature of the
transformation; the
microstructural details
of bainite are so fine
that their resolution is
possible only using
electron microscopy
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 57
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM

58. • Rapid Cooling….
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 58
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
γ austenite Martensite
(BCT structure)
Rapid
cooling
Martensite is a nonequilibrium single-phase structure.
It is a super-saturated solid solution of carbon in ferrite

59. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 59
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
Body Centered Tetragonal Iron atoms
May be
occupied
by carbon
atoms

60. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 60
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
Martensite microstructure

61. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 61
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
Tampered Martensite

62. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 62
EUTECTOID REACTION FOR
IRON-IRON CARBIDE SYSTEM
Tampered Martensite
Tempering is accomplished by heating a martensitic steel to a
temperature below the eutectoid for a specified time period.
Normally, tempering is carried out at temperatures between 250
and 650OC; internal stresses, however, may be relieved at
temperatures as low as 200OC.This tempering heat treatment
allows, by diffusional processes, the formation of tempered
martensite, according to the reaction

63. Just for information…
Tempering is a process of heat treating, which is used to
increase the toughness of iron-based alloys. Tempering is
usually performed after hardening, to reduce some of the
excess hardness, and is done by heating the metal to
some temperature below the critical point for a certain
period of time, then allowing it to cool in still air.
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 63

64. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 64
Tempered
Martensite
Microstructure

65. EUTECTIC REACTION FOR
IRON-IRON CARBIDE SYSTEM
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 65
• Recall….
• What is eutectic reaction ?

66. EUTECTIC REACTION FOR
IRON-IRON CARBIDE SYSTEM
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 66
• Recall….
• What is eutectic reaction ?
EUTECTIC REACTION
Liquid phase
Type-1
solid phase
Type-2
solid phase

67. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 67
EUTECTIC REACTION FOR
IRON-IRON CARBIDE
SYSTEM

68. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 68
EUTECTIC REACTION FOR
IRON-IRON CARBIDE
SYSTEM
Eutectic
Reaction
is at
1147OC
and
4.30 wt% C

69. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 69
EUTECTIC REACTION FOR
IRON-IRON CARBIDE
SYSTEM
Eutectic
Reaction
is at
1147OC
and
4.30 wt% C

70. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 70
EUTECTIC REACTION FOR
IRON-IRON CARBIDE
SYSTEM
Eutectic
Reaction
is at
1147OC
and
4.30 wt% C

71. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 71
EUTECTIC REACTION FOR
IRON-IRON CARBIDE
SYSTEM
During
eutectic
reaction L
phase
transforms in
to eutectic
mixture of
γ and Fe3C.

72. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 72
EUTECTIC REACTION FOR
IRON-IRON CARBIDE
SYSTEM
This
eutectic
mixture of
γ and Fe3C
is called
Ledeburite

73. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 73
EUTECTIC REACTION FOR
IRON-IRON CARBIDE
SYSTEM
Hypoeutectic
Pearlite
+
Ledeburite
+
Cementite
Austenite
+
Ledeburite
+
Cementite

74. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 74
EUTECTIC REACTION FOR
IRON-IRON CARBIDE
SYSTEM
Hypereutectic
Ledeburite
+
Cementite
Ledeburite
+
Cementite
L + Fe3C

75. PERITECTIC REACTION FOR
IRON-IRON CARBIDE SYSTEM
Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 75
• Recall….
• What is Peritectic reaction ?
PERITECTIC REACTION
Type-1
solid phase
Liquid
phase
Type-2 solid phase

76. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 76
PERITECTIC REACTION
FOR
IRON-IRON CARBIDE
SYSTEM
L + Fe3C
Peritectic
Reaction
is at
1493OC
and
0.18 wt% C

77. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 77
PERITECTIC REACTION
FOR
IRON-IRON CARBIDE
SYSTEM
L + Fe3C
Peritectic
Reaction
is at
1493OC
and
0.18 wt% C

78. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 78
PERITECTIC REACTION
FOR
IRON-IRON CARBIDE
SYSTEM
Peritectic
Reaction
is at
1493OC
and
0.18 wt% C
+ L
γ

79. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 79
PERITECTIC REACTION FOR
IRON-IRON CARBIDE SYSTEM
+ L γ
Peritectic
Reaction
• Almost no engineering application
Ferrite + Liquid Austenite

80. Prepared by VISHAL MEHTA || Reference : Material Science and Engineering, An Introduction by William D. Callister, Jr 80
END…