1. B.SREE KRISHNA
116107013
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2. SUPERALLOY
 Superalloy is an alloy that exhibits
excellent mechanical strength and creep
resistance at high temperatures.
 Superalloys are metallic materials for
service at high temperatures ,
particularly in hot zones of gas turbine ,
jet engines etc..
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3. Development of Superalloys
 Superalloys develop high temperature
strength through Solid solution
strengthening(SSS)
 SSS is a type of alloying that can be
used to improve the strength of the
metals
 The technique works by adding atoms of
one element (alloying element) to the
crystalline lattice of another element (the
base metal)
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4. Properties
 High temperature creep resistance
(1050°C to 1200°C)
 Fatigue life
 Corrosion resistance
 Good surface stability
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5. Classification
 Superalloys are often classified into
generations and until today there were five
generations
 The sixth generation is in the form of
project at National Institute of Material
Science in Japan (NIMS)
 First generation superalloys are
characterstic with a relatively huge amount
of chromium in comparision with other
generations
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6.  The second and third generation
contains about 3 wt % and 6 wt % of
rhenium respectively
 Rhenium is a very expensive addition
but leads to an improvement in creep
strength and fatigue resistance
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7. Composition of some Super
alloys
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8.  As an example of fourth generation of
superalloys TMS-138 can be
characterised.
 It was developed in NIMS with the
addition of Mo for increasing the lattice
misfit .
 The excellent creep behaviour at high
temperatures (about 1373K) is attributed
with the recent generation of superalloys
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10.  The representation of the fifth
generation of the superalloys is for
example TMS-169 alloy developed at
NIMS in collaboration with Ishikawajima-
Harima Heavy insdustries co.,Ltd (IHI) in
japan in 2006
 TMS-169 is an advanced superalloy
containing 5 wt % Ru and 4.6 wt % Cr
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11.  TMS 169 with superior high temperature
creep and oxidation resistance by
incorporating further Ru and Cr content
over the composition of fourth
generation alloys
 With Ru additions it will enhance the
phase stability
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12.  Super alloys are classified into three
based on the predominant metal present
in the alloy. They are
 Nickel based Super alloy
 Iron based Super alloy
 Cobalt based Super alloy
With Al,W,Ti as additional elements
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13. Nickel based Super alloy
 Nickel based Super alloys can be either
Solid solution strengthening or
Precipitation hardening.
 Solid solution strengthened alloys such
as Hastelloy are used only in
applications which require very modest
strength
 Most Ni based alloy contain 10-20% Cr,
up to 8% Al and Ti, 5-10% Co, and small
amounts of B , Zr and C
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14. Iron based Super alloy
 Iron based Super alloys are
characterised by high temperature as
well as room temperature strength.
 Apart from this, it will have good
resistance to creep , oxidation, corrosion
and wear
 Oxidation resistance increases with
chromium content
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15. Cobalt based Super alloy
 Cobalt based Super alloys have their
origin in the stellite alloys.
 Cobalt alloys have higher melting points
than nickel alloys.This gives them the
ability to absorb stress to a higher
temperature
 Cobalt alloys show superior thermal
fatigue resistance and weldability over
the nickel alloys
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16. Applications
 Aircraft gas turbines: disks,
combustion chambers, bolts, casings,
shafts, exhaust systems, cases, blades,
vanes, burner cans, afterburners, thrust
reversers
 Steam turbine power plants: bolts,
blades, stack gas re-heaters
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17.  Reciprocating engines: turbochargers,
exhaust valves, hot plugs, valve seat
inserts
 Metal processing: hot-work tools and
dies, casting dies
 Space vehicles: aerodynamically
heated skins, rocket engine parts
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MTT TURBINE SUPERBIKE Y2K

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Engine of Y2K Superbike

20. High temperature steel
 During the 1950s, utility boilers
operating above 1000°F at pressures
above 1500 psi were experiencing
premature failures.
 These failures were initially attributed to
an extremely fine grain size occasioned
by a low temperature solution heat
treatment
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21.  Reheat treatment at higher temperature
to produce coarse grain structure reduce
the incidence of failure
 Results of a subsequent research found
out that carbon content plays a major
role in this along with final solution heat
treatment and not the grain size.
 A new designation was introduced which
incorporated specific heat treatments
and control of carbon.
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22. Importance
 High temperature steels are specially
alloyed steels and are designed for
 High strength
 Impact toughness
 Wear resistance
The main categories of this steels are
 High-speed steels(HSS)
 Hot-work steels
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23. High speed steels
 It was first developed in the early 1900s,
and are the most highly alloyed steels
which can maintain their hardness and
strength at elevated operating
temperatures
 There are two basic types of high-speed
steels
 Molybdenum type
 Tungsten type
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24. Hot-work steels
 These are designated for use at
elevated temperatures and have high
toughness and high resistance to wear
and cracking.
 The alloying elements are generally
tungsten ,molybdenum , chromium and
vanadium
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25. Applications
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Kawasaki H1 – Engine exhaust

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Valves used in combustion chamber

27. References
 http://www.msm.cam.ac.uk/phase-
trans/2003/Superalloys/superalloys.html.
 http://www.patentstorm.us/patents/5366
695.html
 Manufacturing process for engineering
materials by Kalpakjian
 Material science and Engg by William
callister
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