ME Metallurgy and Phase Diagrams

Question 1

On the iron-iron carbide (Fe-Fe3C) phase diagram, what is the carbon content at the eutectoid composition?

Accepted Answer

0.76 wt% C

Answer

0.022 wt% C

Answer

2.14 wt% C

Answer

4.30 wt% C

Question 2

Pearlite is a microstructure consisting of alternating lamellae of:

Accepted Answer

Ferrite and cementite

Answer

Austenite and ferrite

Answer

Martensite and bainite

Answer

Ledeburite and ferrite

Question 3

Martensite in steel is formed by:

Accepted Answer

Rapid quenching of austenite, preventing diffusion-based transformation

Answer

Slow furnace cooling of austenite

Answer

Tempering of bainite at high temperature

Answer

Prolonged holding at the eutectoid temperature

Question 4

The Gibbs phase rule for a system in equilibrium is expressed as:

Accepted Answer

F = C - P + 2

Answer

F = C + P - 2

Answer

F = C × P - 2

Answer

F = C + P + 2

Question 5

In a binary phase diagram, the lever rule is used to determine:

Accepted Answer

The relative amounts (fractions) of each phase in a two-phase region

Answer

The temperature of a phase transformation

Answer

The crystal structure of each phase

Answer

The diffusion coefficient between two phases

Question 6

Normalizing a steel involves:

Accepted Answer

Heating to the austenite region and air cooling

Answer

Heating to the austenite region and quenching in water

Answer

Heating to just below the eutectoid temperature and slow furnace cooling

Answer

Rapid heating followed by immediate quenching in oil