phase transformation reaction
TRANSCRIPT
PRESENTED BY
ABHIJEET CHOUDHARI
Three Phase Reactions
Peritectic, at 1492°C, with low % of Carbon in
alloys. (almost no engineering importance).
Eutectic, at 1147°C, with 4.3% Carbon, alloys
called cast irons.
Eutectoid, at 727°C with eutectoid
composition of 0.8% Carbon, having two-
phase mixture (ferrite & cementite). They are
steels.
Eutectic, Eutectoid, & Peritectic:
• Peritectic - liquid and one solid phase transform to a 2nd. solid phase
Solid1 + Liquid ↔ Solid2
+ L ß
Eutectic - liquid transforms to two solid phases
L +
• Eutectoid – one solid phase transforms to two other solid phases
Solid1 ↔ Solid2 + Solid3
+ Fe3C + α
Eutectoid reaction
Redistribution of carbon by diffusion
Austenite – 0.76 wt% CFerrite - 0.022 wt% CCementite - 6.70 wt% C
Pearlitey↔α+ Fe3C
Simplified Iron-Carbon phase diagram austenite ↔ pearlite (mixture of ferrite & cementite)
Nucleation & growth of pearlite
Schematic picture of the formation and growth of pearlite
Ferrite (α) Cementite
Principal phases of steel and their Characteristics
SUMMARY
Basically in Eutectoid reactions, a single solid
converts into two different solids while
cooling at Eutectoid temperature.
eg: Fe-C, Cu-Sn, Cu-Al, Zn-Al, Al-Mn, etc.
ANY QUARIES.......
Referances....
• Material science & Metallurgy By V.D. Kodgire, S.V. Kodgire.
• Google, Wekipedia.
THANK YOU…!