Download - LECTURE 06_Nickel and Its Alloys
Suranaree University of Technology May-Aug 2007
Nickel and its alloysNickel and its alloys
Subjects of interest
• Objectives/Introduction
• Production of nickel and nickel alloys
• Commercially pure nickel
• Nickel-copper alloys (Monels)
• Nickel-chromium alloys
• Nickel-base superalloys
• Single crystal castings of nickel-base
superalloys
Lecture 6
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
ObjectivesObjectives
• This chapter provides fundamental knowledge of
different methods of productions of nickel alloys and the
use of various types of nickel alloys.
• The influences of alloy composition and microstructure
on chemical and mechanical properties of nickel alloys will
be discussed in relation to its applications.
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
IntroductionIntroduction
Properties
• Silvery shiny appearance
• High toughness and ductility
• Good high and low
temperature strength
• High oxidation resistance
• Good corrosion resistance
• Ferro-magnetic
• Relatively high cost
• Not mixed with cheap
alloying elements.
Limitations
Nickel
Ni
Crystal structure FCC
Atomic number 28
Atomic weight 58.71
Density (g.cm-3) 8.89
Melting point (oC) 1455
28
58.71
FCC
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
ApplicationsApplications
• Applications required necessary corrosion or heat- resisting
properties and for special engineering applications.
• Chemical plant, heat exchanger, reaction furnace, rotary kiln,
turbine blades.
• Used as alloying elements in stainless steels, and in other
elements such as copper, cobalt, chromium, etc.
Aerospace flow bodies
www.immnet.com
Turbine blades
www.msm.cam.ac.uk
Heat exchangersReaction furnace
Rotary kiln
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
Production of nickelProduction of nickel
www.mii.org
First discovery of nickel mineral by the German was
mistakenly misunderstood to be rich-copper mineral.
There are three major types of nickel deposits (sources):
1) Nickel-copper sulphide
2) Nickel silicates
3) Nickel laterites and serpentines
Nickel laterite deposits
research.eas.ualberta.ca/ egg/nilaterite.jpg Nickeline or niccolite
Serpentine deposits
home.arcor.de
Tapany Udomphol
Extraction of nickelExtraction of nickel
Nickel-sulphide ore
(Fe, Cu)
Crushing
Grinding
Magnetic separation
Iron sulphide
(pyrrhotite
concentrate)
Iron ore
recovery plant
Froth flotation treatment
Nickel concentrate Copper concentrate
Remaining ore
(Ni, Cu)
Copper
smelter
Roasting
Smelting(Reverberatory furnace)
Bessemer matte
(Ni and Cu sulphides)
Recrystallisation
Cooling
Crushing & grinding
Crystals of Ni and Cu
sulphides.
Ni-Cu metallic alloy
Froth flotation
Copper sulphide Nickel sulphide
Different grade
of nickel oxides
Roasting
Nickel refinery
Pure nickel and
other nickel alloy
products
Suranaree University of Technology May-Aug 2007Tapany Udomphol
Suranaree University of Technology May-Aug 2007
Classification of nickel alloysClassification of nickel alloys
There are different types of nickel and nickel alloys;
1) Commercially pure nickel
2) Nickel-copper alloys (Monels)
3) Nickel-chromium alloys
4) Nickel-base superalloys
5) Nickel-iron superalloys
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
Commercially pure nickelCommercially pure nickel
• High purity nickel contains 99.99% Ni.
• Commercially pure nickel contains
99.5% Ni (+Co).
• Microstructure consists of solid solution
phase in annealed condition.
Cold drawn Nickel 200 annealed
at 829oC
Properties
• Good mechanical properties
and retains its strength at
elevated temperature.
• Excellent resistance to most
corrosive environment.
Applications
• Food processing equipment
• Electrical & electronic parts
• Caustic handling equipment.
100 x
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
NickelNickel--copper alloys (copper alloys (MonelsMonels))
• Ni and Cu form complete solid solution.
• Most important Ni-Cu alloy contains
67%Ni and 33%Cu, called Monels.
Properties
Applications
• High strength and toughness over
a range of temperature.
• Good weldability
• Excellent corrosion resistance
Microstructure of
cold drawn Monel
R405 and
annealed at 829oC,
showing solid
solution phase of
Ni-Cu with
sulphide stringers
(black)
• Values, pumps, marine fixtures
and fasteners.
• Chemical processing equipment.
• Oil-well drill collars and
instruments.
Ni-Cu phase diagram
250 xTapany Udomphol
Suranaree University of Technology May-Aug 2007
NickelNickel--chromium alloyschromium alloys
• Cr forms solid solution with Ni up to~30%
at RT. High corrosion resistance is due to
high Cr addition.
• Inconel 600 (15.5%Cr, 8%Fe) is a
standard engineering alloy. Other Ni-Cr
alloys are Inconel 601 and 625 with
improved properties.
Ni-Cr phase diagram
Properties
Applications
• High corrosion resistance at
high temperature.
• High strength and workability.
• Heat exchanger tubing
• Chemical and food
processing equipment.
• Furnace muffle.
Inconel 600, solution
heat-treated at
1200oC/1h+870oC/4h,
showing solid solution
phase with chromium
carbide precipitates at
GBs and some titanium
carbides and nitrides
within the grains1500 x
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
NickelNickel--base base superalloyssuperalloys
• High temperature heat-resistance alloys, which can retain
high strengths at elevated temperatures.
Properties
Applications
• Heat resistant and high strength at high
temperature (760-980oC).
• Good corrosion resistance.
• Good oxidation resistance.
• There are three types of Ni-base superalloys; nickel base, nickel-
iron base and cobalt base. The alloys contain high Cr with Ti, Al to
from precipitates and additions of Mo, Co, Nb, Zr, B, Fe.
• Microstructures are complex.
• Aircrafts, space vehicles, rocket engines
• Industrial gas turbines, high temp applications.
• Nuclear reactors, submarines.
• Steam power plants, petrochemical equipment.
www.stratcor.com
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
Microstructure of nickel base Microstructure of nickel base superalloyssuperalloys
The major phases present in the nickel-base superalloys:
1)1)1)1) γγγγ (gamma) phase – the continuous matrix of FCC austenite.
2)2)2)2) γγγγ’ (gamma prime) phase – the major precipitate phase (more cubic shape).
3) Carbides –various types, mainly M23C6 and MC. M = metal.
Complex microstructure of astroloy
forging after heat treatments
10,000 x
Carbides
at GB
Note: GB carbides affect high-temp strength, ductility, creep.
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
NickelNickel-- iron iron superalloyssuperalloys
• Fe is added to replace some of Ni as it has lower cost.� lowering
the properties as compared with nickel base superalloy. �
therefore it is used at lower temperatures.
• Ni-Fe superalloys contains 25-45%Ni and 15-60%Fe.
• Higher Ni content increases operating temp (upto 815oC), due to
improved stability but more costly.
• Ex: Inconel 707, 718, 901.
• Microstructure consists of
austenistic FCC matrix and can
be strengthened by solid solution
strengthening (Mo, Cr), and
precipitation hardening (Ti, Nb, Al)
by forming intermetallic phases. 15,000 x
Optical micrograph of
Inconel 901 after
precipitation hardening
SEM micrograph of Inconel 718
after exposure at 705oC/6,048
h, 37 ksi
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
SingleSingle--crystal castings of crystal castings of
nickelnickel--base base superalloyssuperalloys
• A major increase in strength and temperature capability of
superalloy casting has been much improve with the introduction of
columnar-grained and single crystal casting.
Diagram of setup
for single crystal
casting
www.nap.edu
Simulation of
evolution of grain
structure in a single
crystal casting.
Turbines blades are
cast using a spiral
starter
Competitive
grain
www.msm.cam.ac.uk
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
Applications of singleApplications of single--crystal castings of crystal castings of
nickelnickel--base base superalloyssuperalloys
• Used in production of aerofoils, gas turbine engines,
which allow the operating temperature range ~ 50oC higher
than normal materials.
Single crystal casting
of superalloy
www.grc.nasa.gov
Property
comparison
between
polycrystal,
columnar
crystal and
single crystal
(a) Polycrystal (b) Columnar
crystal
(c) Single
crystal
Tapany Udomphol
Suranaree University of Technology May-Aug 2007
ReferencesReferences
• ���� �������, � �����กก ����� �ก, 2536, ����ก�������� �ก����� �!" �", ISBN
974-582-155-1.
• Smith, W.F., Structure and properties of engineering
alloys, second edition, 1993, McGraw-Hill, ISB 0-07-59172-5.
• www.cda.org.uk.
• Heußner, U., Nickel alloys, 1998, Marcel Dekker, Inc., ISBN
0-8247-0440-1.
Tapany Udomphol