ME Metals and Alloys

Question 1

Which crystal structure do most face-centered cubic (FCC) metals exhibit at room temperature?

Accepted Answer

FCC

Answer

BCC

Answer

HCP

Answer

Simple cubic

Question 2

The iron-carbon phase diagram shows that the maximum solubility of carbon in austenite (FCC iron) is approximately:

Accepted Answer

2.14 wt%

Answer

0.02 wt%

Answer

0.77 wt%

Answer

6.67 wt%

Question 3

The eutectoid composition in the iron-carbon system is approximately:

Accepted Answer

0.77 wt% C

Answer

0.02 wt% C

Answer

2.14 wt% C

Answer

4.30 wt% C

Question 4

Age hardening (precipitation hardening) in aluminum alloys involves which sequence of steps?

Accepted Answer

Solution treatment, quenching, aging

Answer

Annealing, quenching, cold work

Answer

Normalizing, tempering, aging

Answer

Cold work, annealing, quenching

Question 5

Martensite in steel is formed by:

Accepted Answer

Rapid quenching that suppresses diffusional transformation

Answer

Slow cooling through the eutectoid temperature

Answer

Extended annealing at low temperatures

Answer

Hot rolling followed by air cooling

Question 6

Which alloying element is primarily added to steel to improve hardenability?

Accepted Answer

Chromium

Answer

Silicon

Answer

Sulfur

Answer

Lead