M6.2 Flashcards
What is a non-ferrous metal?
- Does not contain iron as it’s base material
- non-magnetic
- aluminium, copper, titanium, magnesium -> common in aircraft construction and repair
Advantages of aluminium alloyed with copper or zinc?
- strong as steel
- Only 1/3 of weight of steel
What are the 2 main classes of aluminium alloys?
- Wrought aluminium alloys
- cast aluminium alloys
Explain the 4 digit index of aluminium alloy?
- 1st > Main alloying ingredient
- 2nd > modification of alloy
- 3rd > no special significance (alloy designator)
What is cladding?
-thin layer of pure aluminium applied at high temp
Common non-ferrous metals used in aircraft construction are?
- magnesium
- Titanium
- Inconel
- Monel
- Copper
Properties of magnesium?
- lightweight
- Strong
- non-magnetic
- lower density compared to aluminium and weights 2/3 as much
Disadvantage of pure magnesium?
- highly susceptibility to corrosion
- easily cracked when form
- burns readily
Where do they use magnesium alloys on an aircraft?
- landing wheels
- engine crankcases
- valve bodies
Pure titanium is how much lighter than stainless steel approximately?
- about 50% and equal in strength
What items are made using titanium on aircraft?
- bolts + fasteners
- flap tracks
- engine compressor blades
- firewalls
- hydraulic pipes (that operate in high temp)
- engine exhaust
Properties of pure titanium?
- soft
- ductile
What are the 2 common nickel alloys?
- Monel
- Inconel
Monel contains?
- 68% nickel
- 29% copper
- small amounts of iron and manganese
Inconel contains?
- 80% nickel
- 14% chromium
- small amounts of iron + other elements
What is heat treatment?
- involvement of heating and cooling of metals in their solid state
- increases properties
What are the 2 types of heat treatment?
- solution heat treatment
- precipitation heat treatment
What is solution heat treatment?
- heating aluminium alloy to allow alloying element to mix with base metal
What is precipitation heat treatment?
- Soft when removed from quench bath
- become hard and gain strength over time
What is natural ageing?
- alloy cooled at room temp
- can take days/weeks
What is annealing?
- softens metal and decreases internal strength
- opposite of hardening
What does T stand for in temper designations?
- alloy underwent solution heat treatment
What does t3 stand for?
- solution heat treated
- followed by strain hardening
What does t4 stand for?
- underwent solution heat treatment
- followed by natural ageing at room temp
What does t6 stand for?
- alloy underwent solution heat treatment
- followed by artificial ageing
Explain strain hardening (known as cold working or work hardening)?
- mechanically working a metal at a temp below its critical range
