Lecture 17 ndash Aluminium and its alloys

Aluminium and its alloys

Engineering Materials and Processes

Reference Text Section

Higgins RA amp Bolton 2010 Materials for Engineers and Technicians 5th ed Butterworth Heinemann

Ch 17

Additional Readings Section

Aluminium and its alloys

Engineering Materials and Processes

Note This lecture closely follows text (Higgins Ch17)

Aluminium (Higgins 171)

Engineering Materials and Processes

READ HIGGINS 171

Aluminium is very reactive ndash strongly electropositive and readily

combines with all the non-metal (electronegative) ions

So it wasnrsquot produced until 1825 (Oersted) when it was more expensive

than gold

Not any more

Aluminium Wikipedia

Aluminium and its alloys

Engineering Materials and Processes

Reference Text Section

Higgins RA amp Bolton 2010 Materials for Engineers and Technicians 5th ed Butterworth Heinemann

Ch 17

Additional Readings Section

Aluminium and its alloys

Engineering Materials and Processes

Note This lecture closely follows text (Higgins Ch17)

Aluminium (Higgins 171)

Engineering Materials and Processes

READ HIGGINS 171

Aluminium is very reactive ndash strongly electropositive and readily

combines with all the non-metal (electronegative) ions

So it wasnrsquot produced until 1825 (Oersted) when it was more expensive

than gold

Not any more

Aluminium Wikipedia

Aluminium and its alloys

Engineering Materials and Processes

Note This lecture closely follows text (Higgins Ch17)

Aluminium (Higgins 171)

Engineering Materials and Processes

READ HIGGINS 171

Aluminium is very reactive ndash strongly electropositive and readily

combines with all the non-metal (electronegative) ions

So it wasnrsquot produced until 1825 (Oersted) when it was more expensive

than gold

Not any more

Aluminium Wikipedia

Aluminium (Higgins 171)

Engineering Materials and Processes

READ HIGGINS 171

Aluminium is very reactive ndash strongly electropositive and readily

combines with all the non-metal (electronegative) ions

So it wasnrsquot produced until 1825 (Oersted) when it was more expensive

than gold

Not any more

Aluminium Wikipedia

Uses of aluminium

Engineering Materials and Processes

httpwwwalu-supportcomnewsdispphpID=129

READ HIGGINS 171

Demand for Aluminium was

driven by aircraft

Today it is widely spread

though most industries

Lightweight

Durable

Easy to form extrude diecast

Good finishes

High strength to weight

Worldwide Aluminium Production

Engineering Materials and Processes

Worldwide Aluminium

production

Aluminium needs electricity

It is actually easier to ship

the ore to the electrical

energy source rather than

bring the electricity to the

ore

Worldwide Aluminium Production

Engineering Materials and Processes

Worldwide Aluminium

production

Aluminium needs electricity

It is actually easier to ship

the ore to the electrical

energy source rather than

bring the electricity to the

ore

The extraction of aluminium (Higgins 172)

Engineering Materials and Processes

READ HIGGINS 172

The modern electrolytic process turns bauxite (Al2O3) into aluminium

metal Unlike a blast furnace that removes oxygen (reduction) with

coke aluminium requires electricity to do this

All 91 megaJoules of the stuff per kg

So aluminium product suits countries

with ample hydroelectricity

(eg Norway)

httpenwikipediaorgwikiFileAluminumSlabJPG

The extraction of aluminium (VIDEO)

Engineering Materials and Processes

VIDEO

The making of aluminium [videorecording]

Advanced version Russell Geoff

1993 Video Education Australia DVD (30 min)

Explains the process of smelting aluminium using

the smelter at Portland smelter in Victoria as an

example

Detailed analysis of refining and smelting of

aluminium Covers production economic

environmental issues Excellent quality

DVD 669722RUSS

The extraction of aluminium (VIDEO)

Engineering Materials and Processes

VIDEO

The making of aluminium [videorecording]

Advanced version Russell Geoff

1993 Video Education Australia DVD (30 min)

Explains the process of smelting aluminium using

the smelter at Portland smelter in Victoria as an

example

Detailed analysis of refining and smelting of

aluminium Covers production economic

environmental issues Excellent quality

DVD 669722RUSS

Properties of aluminium (Higgins 173)

Engineering Materials and Processes

READ HIGGINS 173

Conductivity (electrical and thermal)

Corrosion resistance

Ductility for forming extrudion

Low MP for diecasting

Highly machinable

Lightweight

Good finishes - anodising

High strength to weight

Lots of alloys and heat treatmentshttpwwwteknologiateollisuusfi

Aluminium alloys (Higgins 174)

Engineering Materials and Processes

READ HIGGINS 174

4 main classes of aluminium alloys

Wrought Cast

Non-heat Treatable

Heat Treatable

Traps to watch out forhellip

1 A common mistake is to call aluminium components ldquoalloyrdquo simply

because it starts with ldquoalrdquo Brass and even steel is ldquoalloyrdquo

2 In USA Aluminium is called Aluminum Same stuff different name

Aluminium alloys (Higgins 174)

Engineering Materials and Processes

READ HIGGINS 174

1741 Wrought alloys

1742 Cast alloys

READ HIGGINS 175

175 Wrought alloys which are not heat-treated

176 Cast alloys which are not heat-treated

Some common aluminium alloys

Engineering Materials and Processes

httpwwwglobalmetalscomau

Aluminum alloys

Engineering Materials and Processes

They are normally identified by a four figure system which originated in

the USA and is now universally accepted (with variations ndash usually extra

digits)

Note

Higgins is based on British

Standards (BS) from which

most Australian standards

are based

Where it is written

1473 5083

It simply means

BS 1473 and grade 5083

(eg table 171)

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

Figure 172 The

aluminium-silicon

thermal equilibrium

diagram The effects of

modification on both

the position of the

eutectic point and the

structure are also

shown

READ HIGGINS

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

(i) 12 per cent silicon in aluminium -

unmodified as cast Since this alloy

contains more than the eutectic amount

(116 per cent) of silicon (see Figure 172)

primary silicon (angular crystals) are

present The eutectic is coarse and brittle

and consists of needles of silicon in a

matrix of a solid solution because the layers

of a in the eutectic have fused together to

form a continuous mass (the amount of

silicon being only 116 per cent of the

eutectic so that the layers of a would be

roughly ten times the thickness of those in

silicon)

Engineering Materials and Processes

Higgins

(ii) The same alloy as (i) but modified by

the addition of 001 per cent sodium

This has the effect of displacing the

eutectic point to 14 per cent silicon so

that the structure now consists of

primary crystals of a (light) in a

background of extremely fine-grained

eutectic (dark) The alloy is now

stronger and tougher

Engineering Materials and Processes

Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Aluminium alloys (Higgins 174)

Engineering Materials and Processes

READ HIGGINS 174

4 main classes of aluminium alloys

Wrought Cast

Non-heat Treatable

Heat Treatable

Traps to watch out forhellip

1 A common mistake is to call aluminium components ldquoalloyrdquo simply

because it starts with ldquoalrdquo Brass and even steel is ldquoalloyrdquo

2 In USA Aluminium is called Aluminum Same stuff different name

Aluminium alloys (Higgins 174)

Engineering Materials and Processes

READ HIGGINS 174

1741 Wrought alloys

1742 Cast alloys

READ HIGGINS 175

175 Wrought alloys which are not heat-treated

176 Cast alloys which are not heat-treated

Some common aluminium alloys

Engineering Materials and Processes

httpwwwglobalmetalscomau

Aluminum alloys

Engineering Materials and Processes

They are normally identified by a four figure system which originated in

the USA and is now universally accepted (with variations ndash usually extra

digits)

Note

Higgins is based on British

Standards (BS) from which

most Australian standards

are based

Where it is written

1473 5083

It simply means

BS 1473 and grade 5083

(eg table 171)

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

Figure 172 The

aluminium-silicon

thermal equilibrium

diagram The effects of

modification on both

the position of the

eutectic point and the

structure are also

shown

READ HIGGINS

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

(i) 12 per cent silicon in aluminium -

unmodified as cast Since this alloy

contains more than the eutectic amount

(116 per cent) of silicon (see Figure 172)

primary silicon (angular crystals) are

present The eutectic is coarse and brittle

and consists of needles of silicon in a

matrix of a solid solution because the layers

of a in the eutectic have fused together to

form a continuous mass (the amount of

silicon being only 116 per cent of the

eutectic so that the layers of a would be

roughly ten times the thickness of those in

silicon)

Engineering Materials and Processes

Higgins

(ii) The same alloy as (i) but modified by

the addition of 001 per cent sodium

This has the effect of displacing the

eutectic point to 14 per cent silicon so

that the structure now consists of

primary crystals of a (light) in a

background of extremely fine-grained

eutectic (dark) The alloy is now

stronger and tougher

Engineering Materials and Processes

Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Aluminium alloys (Higgins 174)

Engineering Materials and Processes

READ HIGGINS 174

1741 Wrought alloys

1742 Cast alloys

READ HIGGINS 175

175 Wrought alloys which are not heat-treated

176 Cast alloys which are not heat-treated

Some common aluminium alloys

Engineering Materials and Processes

httpwwwglobalmetalscomau

Aluminum alloys

Engineering Materials and Processes

They are normally identified by a four figure system which originated in

the USA and is now universally accepted (with variations ndash usually extra

digits)

Note

Higgins is based on British

Standards (BS) from which

most Australian standards

are based

Where it is written

1473 5083

It simply means

BS 1473 and grade 5083

(eg table 171)

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

Figure 172 The

aluminium-silicon

thermal equilibrium

diagram The effects of

modification on both

the position of the

eutectic point and the

structure are also

shown

READ HIGGINS

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

(i) 12 per cent silicon in aluminium -

unmodified as cast Since this alloy

contains more than the eutectic amount

(116 per cent) of silicon (see Figure 172)

primary silicon (angular crystals) are

present The eutectic is coarse and brittle

and consists of needles of silicon in a

matrix of a solid solution because the layers

of a in the eutectic have fused together to

form a continuous mass (the amount of

silicon being only 116 per cent of the

eutectic so that the layers of a would be

roughly ten times the thickness of those in

silicon)

Engineering Materials and Processes

Higgins

(ii) The same alloy as (i) but modified by

the addition of 001 per cent sodium

This has the effect of displacing the

eutectic point to 14 per cent silicon so

that the structure now consists of

primary crystals of a (light) in a

background of extremely fine-grained

eutectic (dark) The alloy is now

stronger and tougher

Engineering Materials and Processes

Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Some common aluminium alloys

Engineering Materials and Processes

httpwwwglobalmetalscomau

Aluminum alloys

Engineering Materials and Processes

They are normally identified by a four figure system which originated in

the USA and is now universally accepted (with variations ndash usually extra

digits)

Note

Higgins is based on British

Standards (BS) from which

most Australian standards

are based

Where it is written

1473 5083

It simply means

BS 1473 and grade 5083

(eg table 171)

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

Figure 172 The

aluminium-silicon

thermal equilibrium

diagram The effects of

modification on both

the position of the

eutectic point and the

structure are also

shown

READ HIGGINS

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

(i) 12 per cent silicon in aluminium -

unmodified as cast Since this alloy

contains more than the eutectic amount

(116 per cent) of silicon (see Figure 172)

primary silicon (angular crystals) are

present The eutectic is coarse and brittle

and consists of needles of silicon in a

matrix of a solid solution because the layers

of a in the eutectic have fused together to

form a continuous mass (the amount of

silicon being only 116 per cent of the

eutectic so that the layers of a would be

roughly ten times the thickness of those in

silicon)

Engineering Materials and Processes

Higgins

(ii) The same alloy as (i) but modified by

the addition of 001 per cent sodium

This has the effect of displacing the

eutectic point to 14 per cent silicon so

that the structure now consists of

primary crystals of a (light) in a

background of extremely fine-grained

eutectic (dark) The alloy is now

stronger and tougher

Engineering Materials and Processes

Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Aluminum alloys

Engineering Materials and Processes

They are normally identified by a four figure system which originated in

the USA and is now universally accepted (with variations ndash usually extra

digits)

Note

Higgins is based on British

Standards (BS) from which

most Australian standards

are based

Where it is written

1473 5083

It simply means

BS 1473 and grade 5083

(eg table 171)

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

Figure 172 The

aluminium-silicon

thermal equilibrium

diagram The effects of

modification on both

the position of the

eutectic point and the

structure are also

shown

READ HIGGINS

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

(i) 12 per cent silicon in aluminium -

unmodified as cast Since this alloy

contains more than the eutectic amount

(116 per cent) of silicon (see Figure 172)

primary silicon (angular crystals) are

present The eutectic is coarse and brittle

and consists of needles of silicon in a

matrix of a solid solution because the layers

of a in the eutectic have fused together to

form a continuous mass (the amount of

silicon being only 116 per cent of the

eutectic so that the layers of a would be

roughly ten times the thickness of those in

silicon)

Engineering Materials and Processes

Higgins

(ii) The same alloy as (i) but modified by

the addition of 001 per cent sodium

This has the effect of displacing the

eutectic point to 14 per cent silicon so

that the structure now consists of

primary crystals of a (light) in a

background of extremely fine-grained

eutectic (dark) The alloy is now

stronger and tougher

Engineering Materials and Processes

Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

Figure 172 The

aluminium-silicon

thermal equilibrium

diagram The effects of

modification on both

the position of the

eutectic point and the

structure are also

shown

READ HIGGINS

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

(i) 12 per cent silicon in aluminium -

unmodified as cast Since this alloy

contains more than the eutectic amount

(116 per cent) of silicon (see Figure 172)

primary silicon (angular crystals) are

present The eutectic is coarse and brittle

and consists of needles of silicon in a

matrix of a solid solution because the layers

of a in the eutectic have fused together to

form a continuous mass (the amount of

silicon being only 116 per cent of the

eutectic so that the layers of a would be

roughly ten times the thickness of those in

silicon)

Engineering Materials and Processes

Higgins

(ii) The same alloy as (i) but modified by

the addition of 001 per cent sodium

This has the effect of displacing the

eutectic point to 14 per cent silicon so

that the structure now consists of

primary crystals of a (light) in a

background of extremely fine-grained

eutectic (dark) The alloy is now

stronger and tougher

Engineering Materials and Processes

Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Engineering Materials and Processes

Higgins

Figure 172 The

aluminium-silicon

thermal equilibrium

diagram The effects of

modification on both

the position of the

eutectic point and the

structure are also

shown

READ HIGGINS

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

(i) 12 per cent silicon in aluminium -

unmodified as cast Since this alloy

contains more than the eutectic amount

(116 per cent) of silicon (see Figure 172)

primary silicon (angular crystals) are

present The eutectic is coarse and brittle

and consists of needles of silicon in a

matrix of a solid solution because the layers

of a in the eutectic have fused together to

form a continuous mass (the amount of

silicon being only 116 per cent of the

eutectic so that the layers of a would be

roughly ten times the thickness of those in

silicon)

Engineering Materials and Processes

Higgins

(ii) The same alloy as (i) but modified by

the addition of 001 per cent sodium

This has the effect of displacing the

eutectic point to 14 per cent silicon so

that the structure now consists of

primary crystals of a (light) in a

background of extremely fine-grained

eutectic (dark) The alloy is now

stronger and tougher

Engineering Materials and Processes

Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Engineering Materials and Processes

Higgins

Engineering Materials and Processes

Higgins

(i) 12 per cent silicon in aluminium -

unmodified as cast Since this alloy

contains more than the eutectic amount

(116 per cent) of silicon (see Figure 172)

primary silicon (angular crystals) are

present The eutectic is coarse and brittle

and consists of needles of silicon in a

matrix of a solid solution because the layers

of a in the eutectic have fused together to

form a continuous mass (the amount of

silicon being only 116 per cent of the

eutectic so that the layers of a would be

roughly ten times the thickness of those in

silicon)

Engineering Materials and Processes

Higgins

(ii) The same alloy as (i) but modified by

the addition of 001 per cent sodium

This has the effect of displacing the

eutectic point to 14 per cent silicon so

that the structure now consists of

primary crystals of a (light) in a

background of extremely fine-grained

eutectic (dark) The alloy is now

stronger and tougher

Engineering Materials and Processes

Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Engineering Materials and Processes

Higgins

(i) 12 per cent silicon in aluminium -

unmodified as cast Since this alloy

contains more than the eutectic amount

(116 per cent) of silicon (see Figure 172)

primary silicon (angular crystals) are

present The eutectic is coarse and brittle

and consists of needles of silicon in a

matrix of a solid solution because the layers

of a in the eutectic have fused together to

form a continuous mass (the amount of

silicon being only 116 per cent of the

eutectic so that the layers of a would be

roughly ten times the thickness of those in

silicon)

Engineering Materials and Processes

Higgins

(ii) The same alloy as (i) but modified by

the addition of 001 per cent sodium

This has the effect of displacing the

eutectic point to 14 per cent silicon so

that the structure now consists of

primary crystals of a (light) in a

background of extremely fine-grained

eutectic (dark) The alloy is now

stronger and tougher

Engineering Materials and Processes

Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

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Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

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Engineering Materials and Processes

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Aluminium

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Higgins

(ii) The same alloy as (i) but modified by

the addition of 001 per cent sodium

This has the effect of displacing the

eutectic point to 14 per cent silicon so

that the structure now consists of

primary crystals of a (light) in a

background of extremely fine-grained

eutectic (dark) The alloy is now

stronger and tougher

Engineering Materials and Processes

Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

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Higgins

(iii) A duralumin- type alloy in the as

extruded condition (unetched) The

particles consist mainly of CuAl2 (see

Figure 174) elongated in the direction

of extrusion

Most of this CuAl2 would be absorbed

during subsequent solution treatment

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 174

Structural

changes

which take

place during

the heat-

treatment of

a duralumin-

type of alloy

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

Figure 175 The effects of time and temperature of precipitation treatment

on the strength of duralumin

Higgins

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Wrought alloys which are heat-treated (Higgins 177)

Engineering Materials and Processes

CAREFULLY READ

1771 Heat-treatment

Age Hardening

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Engineering Materials and Processes

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Engineering Materials and Processes

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Cast alloys which are heat-treated (Higgins 178)

Engineering Materials and Processes

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

Engineering Materials and Processes

Online Resources

Aluminium

Non Ferrous Metals

GLOSSARY

Bauxite

Electrolysis

Precipitation hardening

Age hardening

Wrought

Cast

Anodising

Oxide layer

As quenched

Alumina

Engineering Materials and Processes

Glossary

httpwwwamari-irelandcomonline-toolsglossaryaluminiuma

QUESTIONSMoodle XML Some questions in 10106 Non-Ferrous

1 Define all the glossary terms

2 Aluminium has been dubbed solid electricity Producing 1 kg of Aluminium uses 91

MJ Calculate the cost to produce 1 kg of aluminium based on current domestic

electricity charges What rate would you expect a smelter to pay

3 It has been stated that aluminium is the most economically viable material for

recycling Comment on this statement using a comparison of current recycling

values for other common scrap materials like metals plastics and paper products

Ref httpenwikipediaorgwikiAluminium List the proportions of Aluminium that

are lost during recycling

4 Why have car radiators switched from copper to aluminium Explain why these

two metals dominate other areas like evaporators and condensers in air

conditioning and heat exchangers for heat reclamation systems for reducing

energy losses in manufacturing and process plants

5 Explain the age hardening process and mechanism for an aluminium alloy such as

Duralumin

6 Explain why Aluminium is highly reactive yet is used for its corrosion resistance

Engineering Materials and Processes