6.2 Flashcards
Why are titanium and it’s alloys used in the aircraft industry?
High strength
Light weight
Temperature resistance
Corrosion resistance
How does titanium compare to steel?
Same strength
56% of the weight
Where is titanium used in an aircraft?
Cooler sections of the gas turbine engines
Cowlings and baffles
Skin parts that are subjected to high temperatures
What does titanium have excellent resistance to?
Oxidising acids
Nitric or chromic acids
What will attack titanium?
Strong reducing acids and chlorinated cleaning solutions
What is titanium completely inert from?
Stagnant water Urban atmosphere Marine atmosphere Salt water spray Sea water
What type of welding is one of the best for welding titanium?
Inert-gas welding
How much carbon and nitrogen does pure titanium have?
Carbon- 0.10%
Nitrogen- 0.05%
(Maximum)
What is the tensile strength of pure titanium?
50,000-90,000 psi
What is the tensile strength of titanium with manganese added?
139,000 psi
How much aluminium is commonly used with titanium?
3-7%
What is the highest tensile strength a titanium alloy can be?
180,000 psi
What is important for the cutting dies and shear blades when being used on titanium?
Good quality steel
Sharp
What is titanium a poor conductor of?
Heat
What’s the best way to machine titanium?
Low cutting speed
High feed rates
Use lots of cutting fluid
Use sharp tools and replace upon first signs of wear
Never stop feeding while surfaces are in contact
What wil titanium do at 1950^F (1065^C)?
Ignite in the presence of oxygen and burn with an incandescent flame
When will titanium ignite with nitrogen?
1500^F (815^C)
Is pure cast aluminium corrosion resistant?
Yes
Is pure aluminium malleable?
Yes
Is pure aluminium heavy?
No
What is the grain structure in cast aluminium?
Coarse
What is the grain structure in wrought aluminium?
Compressed and tightened
How many times lighter is aluminium than steel?
3x
Is aluminium corrosion resistant?
Yes
Is copper a better electrical conductor than aluminium?
No
What is the melting point of aluminium?
660^C
What is the density of aluminium?
2.7 Kg/dm^3
What is the tensile strength of aluminium?
80 N/mm
Alloyed can be up to 540 N/mm
What is the sheeting that covers aluminium to create Alclad?
1% zinc on both sides
How thick are the clad layers on alclad?
3-5% of the material thickness of the aluminium
Aluminium designation system (wrought alloys)
1XXX 99.00% minimum aluminium 2XXX Copper 3XXX Manganese 4XXX Silicon 5XXX Magnesium 6XXX Magnesium and Silicon 7XXX Zinc 8XXX Other elements 9XXX Unused series
Designation system for aluminium (cast alloys)
1XXX 99.00% 2XXX Copper 3XXX Silicon with added copper and/or magnesium 4XXX Silicon 5XXX Magnesium 6XXX Unused series 7XXX Zinc 8XXX Tin 9XXX Other elements
Explanation of alclad numbering system
A 2 0 24 - T3
A= Alclad-covering
2= copper the main alloying ingredient
0= Modification of alloy
24= alloy designator
T3= Solution heat treated, aged, and cold worked
What is work hardending also known as?
Strain hardening
Cold working
What is work hardening?
The strengthening of a metal by plastic deformation
What is annealing?
The heating of alloys, holding or soaking them, the letting them slowly cool in a still air or switched off furnace
What is solution heat treatment?
When metals are heated in molten sodium or potassium nitrate or in a hot furnace. The temp. is then held within plus or minus 50^C, the cooled or quenched rapidly
What does cold working do?
Causes copper to precipitate at grain boundaries and harden the alloys
What is natural age hardening?
Occurs at room temp.
Copper precipitates at the grade boundaries. This hardens the metal to full strength over a period of days
What is artificial aging/precipitation hardening?
Where the temp. is raised to 120^C to 190^C
How many times can a clad material be heat treated?
3
Basic temper designation
F= As fabricated O= Annealed H= strain hardened W= solution heat treated T= heat treated to produce stable tempers other than F, O or H
Is magnesium heavier of lighter than aluminium?
Lighter
Why isn’t pure aluminium used?
Highly susceptible to corrosion
Difficult to work with
Highly flammable
What are the advantages of magnesium?
High strength to weight ratio
Non magnetic
What does Glare stand for?
Glass Reinforced Laminate
What family is Glare part of?
Fibre Metal Laminates (FML)
What advantages do FML’s have?
High strength Fatigue resistance Damage tolerant Impact and blast resistant Fire resistant Thermal isolation
Where on the aircraft can Glare be used?
Leading edges
Blast resistant containers
Cargo floors and liners
