1.
Explain the differences in the shape of the micro-structures of the primary phases formed during
an eutectic transformation and the pro-eutectoid phases formed during an eutectoid
transformation.
Solution
Solution:
The eutectic and eutectoid reactions are the invariant reactions, formed during various systems
like Sn-Pb (lead - tin systems) and Fe-C systems.
During solidification of an alloy having composition prior to the composition of eutectic and
eutectoid, proeutectic phase forms at the more active centres like grain boundaries or grain
corners, and followed by the actual invariant reaction called eutecic or eutectoid.
The difference between the proeutectioid and primary phases formed during the solidicaton prior
to the eutectic reaction is that the active position of primary phase. like grain corners, grain
boundaries. This will be a microstructural difference between these two.