The microstructure is now a ploycrystalline pearlite with the hard-brittle proeutectoid cementite on the grain boundaries. This structure makes the alloy more brittle than the eutectoid pearlite ...

In cooling through this zone, ferrite is precipitated on the austenite grain boundaries. As the temperature is reduced ... The ductility of the ferrite makes this alloy more ductile than the eutectoid ...