6.2- Aircraft Materials Non Ferrous Flashcards
What is a non-ferrous metal?
One that does not contain iron as its base.
What ore does aluminium come from?
Bauxite
What are the most common alloying elements for aluminum?
Copper
Magnesium
Manganese
Zinc
Which alloying elements give aluminium the same strength as steel but third the weight?
Copper and zinc
What is the name of the standards that give aluminium alloys two classes?
H35.1 and H35.2 American national standards institute.
What are the two classes of aluminium alloys?
Wrought
Cast
What is a Wrought Aluminium alloy?
Compressed and tightened grain structure, used extensively in aircraft and can be heat treated.
What is cast aluminium alloy?
Brittle due to their coarse grain. Poured whilst molten for large components.
How are wrought aluminium’s designated?
4 digit system
What are the major wrought aluminium numbers?
1xxx Pure
2xxx Copper
8xxx Other elements
9xxx Unused
How does the 4 digit system break down?
1st Digit- Major element
2nd- Modifications
3/4th- Other elements
What are the two most common 4 digit alloys found on aircraft?
2024 and 7075
Can pure aluminium be strain hardened?
Yes
Where is pure aluminium used?
Electrical and chemical applications
What is the difference between pure aluminium 1100 and 1350?
Both are pure but 1100 is 99.00% aluminium and 1350 is 99.50%
What is the issue with 2xxx copper series?
Susceptible to intergranular corrosion when incorrectly heat treated.
What are the key characteristics of 3xxx manganese series?
Non heat treatable, moderate strength and good working.
What is the benefit to 4xxx silicon series?
Lowers a metals melting temp, ideal for welding?
What makes 5xxx magnesium series more susceptible to corrosion?
Excessive cold working or high temps
Whats different about 6xxx series?
They have two alloying elements, silicon and magnesium, they make magnesium silicide.
What series and alloying element is used when high strength and elasticity is needed?
8090, lithium.
What percentage of the thickness is cladding?
3-5%
How are clad sheets identified?
With the letters, A, AL-clad, Clad or ALC.
What is important about the direction of the al clad designation text?
Shows the direction of the grain.
What is the name of the most popular magnesium alloy?
AZ31
What are magnesium alloys used for?
Flat parts to be attached to the ribs or brackets.
What are the disadvantages of magnesium?
Highly susceptible to corrosion
Easily crack when formed
How are magnesium fires put out?
Smothered with dry sand.
What is pure titanium’s strength and weight compared to iron?
50% lighter same strength.
How does titanium become corrosion resistant?
It reacts with the oxygen to form titanium oxide on the surface.
How are titanium alloys classified?
Alpha
Alpha-beta
Beta
What is an alpha alloy?
Has medium strength and good elevated temp strength.
What is the standard ident for alpha alloy?
Ti-8Al-1Mo-1V
What is an alpha beta alloy?
Most versatile. Medium strength in the annealed condition and much higher strength when heat treated, not weldable.
What is a beta alloy?
Medium strength, excellent forming and contain large amounts of high density alloying elements.
What happens when titanium is added to high temp nickel-cobalt-chromium?
Produces a precipitation hardening reaction which provides strength at temps up to 815c.
What percentage of modern aircraft structures include titanium?
10-15%
What examples are uses for titanium in aircraft?
Bolts and fasteners
Flap tracks
Engine compressor blades
Firewalls
Hydraulic pipes in high temps
What are the two most common nickel alloys?
Monel
Inconel
What percentages are monel nickel alloys?
68% nickel and 29% copper with small amounts of iron and manganese.
Where does monel work well?
Gears and parts where high strength and toughness and rivets.
What percentages are in inconel?
80% nickel and 14% chromium.
What are the most common copper base alloys?
Brass
Bronze
Beryllium
What is brass?
Copper alloy used in bushings, fuel metering valves and electrical plugs.
What is bronze?
Copper alloy containing tin.
What are the two types of heat treatment on aluminium alloys?
Precipitation and Solution
How are 2017 and 2024 treated?
Solution treated then 96 hours cooling/ageing at room temp.
How does solution heat treatment work?
Heated in a salt bath or hot air furnace just below melting point. Held at temp then quenched in water.
When solution heat treating what is the maximum time between removing from treatment and quenching?
10 seconds
Why is quenching after solution heat treating always hot water?
Minimises distortion and alleviates cracking.
Where can spray quenching not be used?
On bare 2017 or 2024.
What is natural ageing?
When cooled at room temp.
What percentage strength does copper ally 2024 have after 30 minutes of natural ageing?
90%
How can the ageing process be slowed down?
Storing at -20c
How can the ageing process be sped up?
Reheating at 160-260c
What are some the names for ageing that is not natural?
Artificial Age Hardening
Precipitation Hardening
Precipitation Heat Treatment
What does annealing do?
Softens a metal and decreases internal stress.
How is annealing carried out?
Heated and held at 415c then cooled to 260c at 25c an hour.
What are the most common temper designations?
T- Solution
T3- Solution then strain hardened
T4- Solution then natural ageing
T6- Solution then Artificial aged
What alloys are non heat treatable?
1xxx
3xxx
5xxx
How can non heat treatable alloys be adjusted?
Cold work or cold rolling
What is cold work or cold rolling also known as?
Strain hardening.
What is the hardness designation F?
As fabricated
What is the hardness designation O?
Annealed
What is the hardness designation H?
Strain hardened
What is the hardness designation H1?
Strain hardened only
What is the hardness designation H2?
Strain hardened and partially annealed.
What is the hardness designation H3?
Strain hardened and stabilised.
Temper designations- what do the digits after the designation (Hx2) represent?
The hardness.
2- Quarter hard
8- Full Hard
What are the most frequently tested properties?
Hardness
Tensile Strength
Fatigue Strength
Impact Resistance
What are the three common methods of hardness testing?
Brinell
Vickers
Rockwell
What is the defined test specification for the brinell test?
ASTM E10
How does the brinell test work?
Hydraulic press with ball end, measure the indentation left behind.
What is the Vickers test also known as?
Microhardness test.
What are the advantages of the Vickers test?
Accuracy does not change with depth change
Only tiny idents made
What are Vickers tests used for?
Small parts and thin sections.
What is the most commonly used hardness test?
Rockwell
What is the Rockwell test defined by?
ATSM E-18
How is a Rockwell tester zeroed?
Minor load is applied (10kg)
What three types of penetrators does a Rockwell tester use?
Conical diamond
1/16in ball
1/8in ball
What are the three major loads of a Rockwell tester?
60, 100 and 150kg.
What three brands of portable hardness tester can be found?
Barcol
Riehle
Ernst
What is the Barcol tester for?
Testing hardness of Brass, Copper and aluminium.
Where is the Barcol tester most commonly used?
Composites, to see if resins are cured?
What is the tensile strength point where a material becomes plastic called?
Yield Tensile Strength.
How is the elongation percentage worked out?
Increase in length divided by original length x 100
What is the limit load?
Maximum load that an aircraft is expected to see at any point.
What is the ultimate load?
Although never expected to be met it is the safety limit of loads an aircraft can take, approx. 1.5 times the load limit.
What types of impact testers are there?
Charpy and Izod
What is the difference between Charpy and Izod?
Charpy is 3 point and Izod is single.
What is the most common impact tester?
Charpy V-notch.