What is a Time Temperature curve basically? I have come across this a couple of times while dealing with heat treatment in my industry. A detailed reply to this is most welcome.
You left off a "T" ; it is "time, temperature, transformation". It is a basis to evaluate hardenability of alloy steels. A sample is austenitized, then rapidly cooled to some temperature ,and held at that temperature for a specific time . Then rapidly cooled to room temperature and the microstructure examined . And after one finishes the one year course on steel metallurgy , one can determine what has occurred. Continuous cooling curves are more reflective of the real world but much more difficult to construct so not often used. USSteel had developed the most comprehensive list of TTT curves ; title - "Isothermal Transformation Diagrams " , pub. 1963, Pittsburgh , PA.