Aircraft Materials - Non Ferrous Flashcards
What are the 4 main characteristics of titanium
- High strength
- Light weight
- Corrosion resistance
- Temperature resistance
How does titanium compare to steel
It is 56% of the weight as steel but just as strong
Why must titanium be protected when temperatures are raised above 1000°f
It combines rapidly with oxygen
What is the tensile strength of titanium in its regular form
50,000-90,000 PSI
What sort of tensile strength can be achieved from titanium when alloyed with other metals
180,000 psi
What material is used to cut titanium
Steel and it must be kept very sharp
When machining titanium, what rules must be followed
- Low Speed, High feed
- Use plenty of cutting fluid
- Use sharp tools
At what temperature will titanium ignite in the presence of oxygen
1950°f and 1500°f in the presence of nitrogen
What is the weight difference between steel and aluminium
Aluminium is 1/3 of steels weight and nearly as strong when alloyed
When would cast aluminium be used
In the construction of aircraft wheels and engine crank cases
What type of grain structure does cast aluminium have
A course grain structure, making it very brittle
What type of grain structure does wrought aluminium have
Compressed
How are wrought and cast aluminium identified
By a 4 digit AA (Aluminium association of America) number
What does the first digit of an aluminium AA number usually denote
The major alloying element
What is the melting point and density of aluminium
660°c and 2.7 Kg/dm3
What is 2024 and 7075 normally clad with to increase corrosion resistance
Pure aluminium with 1% zinc
What is the normal thickness of the cladding on alclad
3-5% of the material thickness
What does the direction of the text on alclad indicate
It will follow the metals grain structure
What is work hardening also known as
Strain hardening or cold working
What is work hardening
The strengthening of a material by plastic deformation
What metals are suitable for work hardening
Many non brittle metals with s reasonable high melting point including low carbon steels
What is the annealing process
Heating a metal to an elevated temperature and holding and soaking it for a length of time and then cooled slowly or left to cool in a switched off furnace
What is solution heat treatment
Metal heated in either molten sodium or potassium nitrate bath or in a hot air furnace, once the solution has been soaked for a prescribed amount of time it is quenched
What is the maximum amount of time that an alloy should be removed from a solution heat treatment before being quenched
10 seconds
After solution heat treatment how is a metal then hardened
- Cold working
- Natural age hardening
- Artificial age hardening/precipitation hardening
What is the maximum amount of times a clad material can be heat treated
3 times
What are the basic temper designations
F - As fabricated O - Annealed H - Strain hardened W - Solution heat treated T - Heat treated to stable tempers other than F,O,H
What are T3, T4 and T6
T3 - Solution heat treated and cold worked
T4 - Solution heat treated and naturally aged
T6 - Solution heat treated and artificially aged
Is magnesium lighter or heavier than aluminium
Lighter
What are the 3 main disadvantages of magnesium
- Highly susceptible to corrosion
- Difficult to work with
- Highly flammable
What are the 2 main advantages of aluminium
- Lightweight
- Non magnetic
How heavy is magnesium compared to aluminium
Magnesium is 2/3 the weight of aluminium
Why would magnesium be used for manufacturing instrument casings
Mainly because of its non magnetic properties
What fire extinguishers must not be used when tackling a magnesium fire
C02 or inert gas. They will increase the fires intensity
What is glare used for in construction of aircraft
Fuselage skin, cargo bay liners, aircraft explosion resistant cargo containers
What are the 6 main characteristics of glare
- High strength
- Fatigue resistance
- Damage tolerant
- Fatigue resistant
- Fire resistant
- Thermal isolation
