18. Phase Diagrams III Fe-C System Flashcards Preview

APSC 278 > 18. Phase Diagrams III Fe-C System > Flashcards

Flashcards in 18. Phase Diagrams III Fe-C System Deck (14):
1

What wt% C is pure cementite (Fe3C) formed at?

6.70%

2

What is the 𝛼 phase called?

Ferrite

3

What is the 𝛾 phase called?

Austentite

4

What is the symbol for the ferrite phase?

𝛼

5

What is the symbol for the Austentite phase?

𝛾

6

When a liquid at the eutectic composition of iron and carbon is cooled below the eutectic point what is the substance formed?

Pearlite (a lamellar microstructure)

7

Is ferrite brittle or ductile?

Ductile

8

Is cementite brittle or ductile?

brittle

9

How do you find the weight fraction of pearlite in the 𝛼 + Fe3C region at a non-eutectic composition?

Draw a tie line just above the eutectic isotherm to determine the weight fraction of 𝛾. The 𝛾 present here will all become pearlite.

10

The prefix hypo means _____
(hypo-eutectic)

before
ie before the eutectic composition

11

The prefix hyper means ____
(hyper-eutectic)

after
ie after the eutectic composition

12

The strength of Pearlite increases with _____ interlaminar spacing, S

decreasing

13

Fine pearlite is ____ (weaker/stronger) than coarse pearlite

stronger

14

Why is fine pearlite stronger than coarse pearlite

finer = more grain boundaries = dislocation movement more inhibited = less chance of slip = stronger