Kinetics and Microstructural Control

· The complete T-T-T diagram for a 1080 (eutectoid) carbon steel is shown.
· The starting material for the transformation process is Austenite (γFe) , the thermodynamic reaction below 723 C is: γ -> α + Fe₃C.
· The isothermal transition of Austenite into Pearlite or Bainite is nucleation and diffusive-transport controlled.
· The Martensitic transition is non-diffusive and does not follow Avrami behavior.

From: Guy and Hren, Addison Wesley (1974)