Objective 07: Aluminum Flashcards
What is the density of Aluminum?
2699 kg/m3
How does the weight of Aluminum compare to magnesium and iron?
It is much lighter than iron and heavier than magnesium
What are the properties of Aluminum?
- Lightweight
- Relatively low tensile strength
- Very malleable
- Very ductile
- Very good heat and electrical condutivity
Is Aluminum easily derived?
No
Bauxite
Redish brown ore of a complex mixture of minerals containing mostly aluminum hydroxides
Bayer Process
Caustic leaching process which produces alumina from bauxite
Hall-Heroult Process
Final refining step after Bayer process
What are the steps of the Hall-Herout Process?
- Alumina from Bayer Process is fed to an electrolytic cell in the presence of the mineral cryolite
- An electric current fuses these minerals together to form molten aluminum
- The molten aluminum settles and is tapped off from the bottom of the bed
Aluminum Alloy
Aluminum combined with other metals such as copper, silicon, manganese, zinc, nickel, magnesium, chromium, and lithium with a remarkable range of attributes
What are some applications of Aluminum Alloys?
- Aircraft and spacecraft construction
- Automobile parts
- Industrial plant equipment
- Military hardware
- Domestic implements
How is Aluminum Alloy with Copper made?
- Aluminum is heated above 550ºC
2. The crucible is saturated with copper to form a solution that is 5% copper by weight
Precipitation Hardening of Aluminum Copper
Process by which Aluminum is quenched by cold water so that the copper does not have time to precipitate into copper crystals and instead forms an intermetallic compound (CuAl2)
What is the benefit of Precipitation Hardening to make Aluminum Copper Alloy?
It produces an alloy that is 5-6 times stronger than pure aluminum
How does Precipitation Hardening improve strength in Aluminum Copper Alloy?
The CuAl2 (Copper Aluminide) micro-particles are extremely hard and interfere with the surrounding aluminum atoms by preventing easy slippage of their atomic-plane structures, resulting in hard, strong alloy
What are the benefits of Aluminum-Lithium Alloys and Aluminum Metal Matrix Composites (MCC)?
- Very high strengths
- Heat resistant
- Durable
- Lightweight