Iron Carbon diagram & heat treatment hand written notes:-
Gibbs Phase Rule: -
The Gibbs phase Rule describes the possible number of degrees of freedom in a system at equilibrium, in terms of the number of separate phases and the number of chemical constituents in the system.
This is defined by the formula as
D = C — P + 2
Where,
D = Degree of freedom
C = Number of components
P = Number of phases
Total number of variables in a system is given by
P( C — 1) + 2 = PC — P + 2
Phase Diagram:-
It is also known as equilibrium diagram. The plots showing relations between phases in equilibrium versus composition, pressure and temperature are called phase diagrams. The composition is plotted on X — axis and temperature is plotted on Y — axis at any specified pressure. Pressure is generally taken atmospheric.
Eutectic Point: -
When a liquid phase changes into two different solid phases during cooling or two solid phases change into a single liquid phase during heating, this point is known as eutectic point and this temperature is known as eutectic temperature.
Eutectoid Point: -
When a solid phase changes into two solid phases during cooling and vice versa that point is known as eutectoid point and temperature at this reaction occurs known as eutectoid temperature.
Peritectic Point: -
A binary system when solid and liquid phases changes solid phase on cooling and vice versa on heating, then state of system is known as peritectic point.
Peritectoid Point: -
If a binary phase diagram when two solid phases change to one solid phase, then state of system is known as peritectoid point.
Iron Carbon ( Fe3C) Phase diagram: -
Phase diagram of great technological importance is that of the iron carbon system.
Please read full article and hand written notes here:
