06_Nickel and Its Alloys

7/28/2019 06_Nickel and Its Alloys

1/16

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


2/16


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


3/16


IntroductionIntroductionProperties

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

NickelNi

Crystal structure FCC

Atomic number 28

Atomic weight 58.71Density (g.cm-3) 8.89

Melting point (oC) 1455

28

58.71

FCC

Tapany Udomphol


4/16


ApplicationsApplications

Applications required necessary corrosion or heat- resisting

properties and forspecial 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


5/16


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


6/16

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


7/16


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


8/16


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 829oCProperties

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


9/16


NickelNickel--copper alloys (copper alloys (MonelsMonels))

Niand Cuform complete solid solution.

Most important Ni-Cualloy contains

67%Niand 33%Cu, called Monels.

Properties

Applications

High strength and toughness over

a range of temperature.

Good weldability Excellent corrosion resistance

Microstructure of

cold drawn MonelR405 and

annealed at 829oC,

showing solid

solution phase of

Ni-Cu with

sulphide stringers

(black)

Values, pumps, marine fixturesand fasteners.

Chemical processing equipment.

Oil-well drill collars and

instruments.

Ni-Cu phase diagram

250 xTapany Udomphol


10/16


NickelNickel--chromium alloyschromium alloys

Crforms solid solution with Niup to~30%

at RT. High corrosion resistance is due to

high Craddition.

Inconel 600(15.5%Cr, 8%Fe) is a

standard engineering alloy. OtherNi-Cr

alloys are Inconel 601 and 625with

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 at1200oC/1h+870oC/4h,

showing solid solution

phase with chromium

carbide precipitates at

GBs and some titanium

carbides and nitrideswithin the grains1500 x

Tapany Udomphol


11/16


NickelNickel--basebase 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 ofNi-base superalloys; nickel base, nickel-

iron base and cobalt base. The alloys contain high Crwith Ti, Altofrom precipitates and additions ofMo, 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


12/16


Microstructure of nickel baseMicrostructure of nickel base superalloyssuperalloys

The major phases present in the nickel-base superalloys:

1)1)1)1) (gamma) phase the continuous matrix of FCC austenite.

2)2)2)2) (gamma prime) phase the major precipitate phase

(more cubic shape).

3) Carbides various types, mainly M23C6and MC. M = metal.

Complex microstructure of astroloyforging after heat treatments

10,000 x

Carbides

at GB

Note: GB carbides affect high-temp strength, ductility, creep.

Tapany Udomphol


13/16


NickelNickel-- ironiron superalloyssuperalloys

Fe is added to replace some ofNias 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%Niand 15-60%Fe.

HigherNicontent increases operating temp (upto 815oC), due to

improved stability but more costly.

Ex: Inconel 707, 718, 901.

Microstructure consists of

austenistic FCC matrixand can

be strengthened by solid solutionstrengthening(Mo, Cr), and

precipitation hardening(Ti, Nb, Al)

by forming intermetallic phases. 15,000 xOptical micrograph of

Inconel 901 after

precipitation hardening

SEM micrograph of Inconel 71

after exposure at 705oC/6,048

h, 37 ksi

Tapany Udomphol


14/16


SingleSingle--crystal castings ofcrystal castings of

nickelnickel--basebase superalloyssuperalloys A major increase in strength and temperature capabilityof

superalloycasting 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

Competitivegrain

www.msm.cam.ac.uk

Tapany Udomphol


15/16


Applications of singleApplications of single--crystal castings ofcrystal castings of

nickelnickel--basebase 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,

columnarcrystal and

single crystal

(a) Polycrystal (b) Columnar

crystal

(c) Single

crystal

Tapany Udomphol


16/16


ReferencesReferences

,F, 2536,, ISBN

974-582-155-1.

Smith, W.F., Structure and properties of engineeringalloys, second edition, 1993, McGraw-Hill, ISB 0-07-59172-5.

www.cda.org.uk.

Heuner, U., Nickel alloys, 1998, Marcel Dekker, Inc., ISBN

0-8247-0440-1.

Tapany Udomphol

06_Nickel and Its Alloys

Documents

Transcript of 06_Nickel and Its Alloys