M6.2 non- Ferrous Flashcards
What is a non ferrous metal
Metals that have elements other than iron as their base metal.
Non magnetic
What are the most common non ferrous metals
Aluminium, copper, titanium, magnesium,
What is alimunium obtained from
An ore called Bauxite
What are the characteristics of aluminium
White
Lightweight
Corrosion resistant
Very strong
Lacks sufficient strength
Most widely used metal
What elements are most commonly used for alloy aluminium metal
Copper
Magnesium
Manganese
Zinc
When aluminium is alloyed with copper or zinc what happens
The alloy is as strong as steel, yet only 1/3 of the weight
Good corrosion resistance too
What does ANSI mean
American national standards institute
What are the two main classes of aluminium
Wrought aluminium
Cast aluminium
What is wrought aluminium
Heated and worked aluminium
Elongsted grain structure
What is cast aluminium
Moulded and allowed to cool
Brittle grain structure
What does the first digit mean
Majorly alloying element
What does the second digit mean
Indicates alloy modification
What does the last two digits mean
Identify different alloys in the group
1xxx?
99% pure aluminium
2xxx?
Copper
3xxx?
Manganese
4xxx?
Silicon
5xxx?
Magnesium
6xxx?
Magnesium and silicon
7xxx?
Zinc
8xxx?
Other elements
9xxx?
Unused series
What are the most common alloys digits used in a situation
2024 - copper no mods zinc and magnesium
7075 - zinc no mods zinc magnesium
What is clad aluminium
A thin layer 3-5 of pure aluminium to a base material by the rolling process at high temps
What does cladding ensure
It increases the materials corrosion resistance
What can be printed on the material to identify it has been cladded?
ALCAD, CLAD, ALC
Does the printed ALCAD run along the grain of the material
Yes
What are the miscellaneous non ferrous metals
Magnesium
Titanium
Inconel
Monel
Copper (bronze= copper and tin) (brass= copper and zinc)
What are the advantages of magnesium
Low mass to density ration
Good mechanical properties
Lightweight
Strong
Non magnetic
(Lower density than Al and weights 2/3 of it)
What are the disadvantages of Magnesium alloys
Susceptible to corrosion
Easily cracks when formed (heat it before to prevent cracking)
Burns readily
Pitting corrosion
What is the most common magnesium alloy
AZ31
(3% Al and 1% zinc)
What are magnesium alloys commonly used for
Aircraft landing wheels, engine crank cases, valve bodies
What do you use to put out a magnesium fire
Sand
What are the advantages of titanium alloys
Lightweight
High strength
(Pure titanium 50% lighter than stainless steel)
Soft and ductile
(Density between Al and Iron)
What does titanium do to makes it corrosion resistant
from a thin layer of titanium oxide outside the pure metal
What are Titanium alloys used for in aviation
Bolts
Fasteners
Firewalls
Hydraulic pipes
Engine compressed blades
What are the most commonly used nickel alloys
Monel
Inconel
What does Monel contain
68% nickel 29% copper and small amounts of iron and manganese
What are the advantages of monel
Can be welded
Good machining characteristics
High strength and toughness
Corrosion resistant at elevated temps
(Some monel containing Al are heat treatable creating strength equivalent to steel)
What is monel used for
Gears
Parts of the exhaust
Monel rivets also available
What does Inconel contain
80% nickel 14% chromium and small amounts of iron
What are the advantages of Inconel
Good strength
Corrosion resistant under extremely high temps
(Similar appearance to stainless steel and used in similar places)
What is Inconel used for
Nozzle supports
Fan castings
Blades
(Used in turbine engines)
What are 3 copper based alloys
Brass
Bronze
Beryllium
What are the advantages of copper alloys
Excellent electrical and theremal conductivity
Malleable
Ductile
What are copper alloys most commonly used for
Electrical wiring as it can be
Rolled, drawn, forged, and pressed
What is a simple definition of heat treatment
A series of operations involving the heating and cooling of metals in their solid state
What is the reason for heat treatments
Makes the metal more useful
Harder, stronger and more resistant to impact
Also more ductile and soft
What are the two types of heat treatment for Aluminium alloys
Solution heat treatment
Precipitation heat treatment
What is solution heat treatment
Process of heating an aluminium alloy to allow alloying element to mix with base metal
What is the process of solution heat treatment
the aluminium alloy is heated in a salt bath (of molten sodium or potassium nitrate)
or in a hot-air furnace from 440 °C – 525 °C (825 °F – 980 °F) (just below its melting point)
duration depends on the thickness and type of aluminium alloy
The temperature is maintained at ±5 °C (±10 °F) long enough for the base metal to be taken into the solid solution with the aluminium.
Once the alloy has been sufficiently heated (soaked),
removed from the furnace and quenched in cold water.
no more than ten seconds elapses between removing an alloy from the furnace and quenching the alloy.
What is precipitation heat treatment
Restore strength since material has come out relatively soft after solution heat treatment.
But by precipitation heat treatment become hard and gain strength over time
What are the two types of precipitation heat treatment
Natural ageing
Artificial ageing
What is natural age hardening
Take quenched alloy out and wait days or weeks for alloy to naturally harden.
(Copper 2024 gains 90% of its strength within first 30 mins and comes fully hard within 5 days)
What is artificial age hardening
Process of hardening can be increased of decreased.
Slowed - storing metal at sun zero (-20 degrees c) immediately after removal.
Increased - reheating the metal between 160 - 260 degrees c. And allow to soak.
What is the process of annealing
Heated and held at appropriate temperatures (mass dependent)
Cooled very slowly in still air or a furnace.
(Can be done several times)
What does annealing do to a material
Softens and decreases internal stress
What can go wrong when annealing clad alloys
If heating is not properly controlled when heating clad alloys it causes the core material to mix with the cladding material. Reducing corrosion resistance
Can you use annealed parts no aircraft’s
No
What does T3 mean (temper designator)
Solution heat treated and cold worked
What does T4 mean
Solution heat treated and naturally aged
What does T6 mean
Solution heat treated and artificially aged
How many times can you re heat cladded materials
3, otherwise there could be a diffusion of base material into the cladding, decreasing corrosion resistance
Why would you reheat materials more than once
To relieve stress
What does strain hardening do
alters the grain structure and hardens the alloy by rolling, drawing, or pressing.
What is strain hardening also known as
cold working or work hardening.
At what temperature range is a metal strain hardened
at a temperature below its critical range
What is the different between strain hardening a heat treatable alloy compared to a non heat treatable alloy
Heat treatable alloys have their strength increased by rolling after they have been solution heat treated.
non-heat treatable alloys are hardened in the manufacturing process when they are rolled to their desired dimensions.
Does pure aluminium benefit from heat treatment
No, pure aluminium has no alloying materials therefore does benefit.
What is alloy 3003
3003 is almost identical to pure aluminium, except for a small amount of manganese
therefore does not benefit from being heat treated.
What is alloy 5052 and why is it important when talking about cold working.
Alloy 5052 most important of the non-heat treatable aluminium alloys.
contains 2.5% magnesium and small amount of chromium.
It is used for welded parts such as fuel or oil tanks and for rigid fluid lines.
Its strength is increased by cold working.
What series are non heat treatable aluminium alloys
1xxx, 3xxx, and 5xxx series
Their properties can be altered by cold working or rolling
How can an alloys hardness or temper be indicated
by a letter that is separated from the alloy designation.
A number following the letter to show when basic temper of the alloy is present.
(Sorry this one is confusing :)))))))
What does F mean
F: As fabricated
What does O mean
O: Annealed, re-crystallised (wrought materials only)
What does H mean
H: Strain hardened
What does H1 mean
H1: Strain hardened only
What does H2 mean
H2: Strain hardened and partially annealed
What does H3 mean
H3: Strain hardened and stabilised
