Light Alloys- Magnesium 1 Flashcards

1
Q

Mg applications in WW2

A

First airplane nearly completely designed with Mg. World’s largest bomber contained 19,000lbs of Mg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Mg applications in peace time

A

Transportation, aircraft/aerospace, 3C product, military, healthcare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Crystal structure of Mg

A

hcp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Advantages of Mg

A

Lowest density of all construction metals at 1.74g/cm3 so light construction parts possible. High specific strength. Excellent castability. Good machinability. Improved corrosion resistance with high-purity alloys. High damping properties. Good weldability under inert gases. Integrated recycling possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Disadvantages of Mg

A

Cold working and extrusion abilities very poor due to hcp structure. Low corrosion resistance. Easily flammable with oxygen around melting points. Shrinkage about 4% when solidifying and 5% during cooling. Low toughness and strength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Calcination

A

Cheapest. Heat MgCO3 to produce MgO and mix with petroleum coke and heat to separate O from Mg. Bad for environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Pidgeon process

A

Thermal reduction method. Powdered ferrosilicon and MgO heated under vacuum at 1200°C giving Mg vapour which is then condensed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Dow process

A

Dolomite CaMg(CO3)2 and seawater and treated with HCl to give MgCl2 and put in electrolytic cell to give Mg metal at cathode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many independent slip systems need to be active at the same time for plastic deformation?

A

5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does CRSS compare for twins and slip in Mg?

A

Basal slip lowest. Then {10-12} twin. Then prismatic slip. The pyramidal slip. Then {10-13} twin. Then {10-11} twin highest. All decrease as T increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When is Mg mostly used for engineering applications?

A

When it is alloyed with other elements. Even though 99.8% purity readily available

How well did you know this?
1
Not at all
2
3
4
5
Perfectly