Kelvin Tam

MT2813- Professor Kunal Kothari

Worksheet onIron‐CarbonBinaryPhaseDiagrams

Question 1:

The Eutectic Point is located at a temperature of 1148 degrees Celsius and has a carbon weight concentration of approximately 4.3%. At this point the liquid state transitions into a dual solid phase consisting of Austenite and Cementite. The Eutectoid point is located at a Carbon weight concentration of approximately 0.76% at a temperature of 727 degrees Celsius. Here, Austenite becomes a mixture of Ferrite and Cementite. These points are labeled in the diagram below:

Question 2:

The Eutectic and Eutectoid temperature are 1148 and 727 degrees Celsius, respectively.

Question 3:

Inset A: Phases present are Austenite (gamma) and ferrite (alpha)

W γ=C0−CαC γ−Cα

= 0.4−0.020.76−0.02

=0.514

W α=Cγ−C0

C γ−Cα= 0.76−0.4

0.76−0.02=0.486

Inset B: Phases present are Ferrite (alpha) and Cementite (Fe3C)

W Fe3C=C0−CαCFe3C−Cα

= 0.4−0.026.70−0.02

=0.0569

W α=CFe3C−C0

CFe 3C−Cα= 6.70−0.4

6.70−0.02=0.9431

Question 4:

Inset C: Phases present are Austenite (gamma) and Cementite (Fe3C)

W γ=CFe3C−C0

CFe 3C−C γ= 6.70−1.3

6.70−0.90=0.931

W Fe3C=C0−C γCFe3C−C γ

= 1.3−0.906.70−0.90

=0.069

Inset D: Phases Present are Ferrite (alpha) and Cementite (Fe3C)

W α=CFe3C−C0

CFe 3C−Cα= 6.70−1.3

6.70−0.02=0.808

W Fe3C=C0−CαCFe3C−Cα

= 1.3−0.026.70−0.02

=0.192