The Iron carbon equilibrium diagram (also called the iron carbon phase diagram) is a graphic representation of the respective microstructure states of the alloy iron – carbon (Fe-C) depending on temperature and carbon content.

What is the iron carbon equilibrium diagram?

The Iron carbon equilibrium diagram (also called the iron carbon phase diagram) is a graphic representation of the respective microstructure states of the alloy iron – carbon (Fe-C) depending on temperature and carbon content.

What are the 5 phases presented on the iron iron carbide phase diagram?

Five phases are- α-ferrite (BCC) Fe-C solid solution, γ-austenite (FCC) Fe-C solid solution, δ -ferrite (BCC) Fe-C solid solution, Fe3C (iron carbide) or cementite – an inter- metallic compound and liquid Fe-C solution.

What are the possible phases that can be found on the iron carbon diagram?

For the iron-carbon phase diagram, the phase fields of interest are the ferrite, cementite, austenite, ferrite + cementite, ferrite + austenite, and austenite + cementite phase fields.

What are the solubilities in wt% C of carbon in the α δ and γ forms of iron?

The carbon has different solubilities in the different iron modifications, which form mixed crystals (solid solutions). In α-iron the solubility is only 0.04% (ferrite) and in δ-iron the solubility is 0.36%.

Why is it called iron carbon equilibrium diagram?

The iron carbide is called meta stable phase. Therefore, iron-iron carbide diagram even though technically represents meta stable conditions, can be considered as representing equilibrium changes, under conditions of relatively slow heating and cooling.

What is Eutectoid point in iron carbon diagram?

The location on a phase diagram indicating the eutectoid composition and eutectoid temperature of an alloy. The eutectoid point also indicates the location at which three solid phases co-exist. In the iron-carbon phase diagram, this point indicates a temperature of 1333 F and a carbon content of 0.8%.

Why iron iron carbide equilibrium diagram is not a true equilibrium diagram?

It may be noted that though it is called as equilibrium diagram, it is not a true equilibrium diagram, since equilibrium implies no change of phase with time. In fact, the compound iron carbide decomposes into iron and carbon (graphite).

What are the limitations of iron-carbon phase diagram?

10.9 Two limitations of the iron-iron carbide phase diagram are: 1) The nonequilibrium martensite phase does not appear on the diagram; and 2) The diagram provides no indication as to the time-temperature relationships for the formation of pearlite, bainite, and spheroidite, all of which are composed of the equilibrium …

What is Hypoeutectoid and Hypereutectoid?

(a) A “hypoeutectoid” steel has a carbon concentration less than the eutectoid; on the other hand, a “hypereutectoid” steel has a carbon content greater than the eutectoid. (b) For a hypoeutectoid steel, the proeutectoid ferrite is a microconstituent that formed above the eutectoid temperature.

Why martensite is not showing in FE C diagram?

Martensite is not shown in the equilibrium phase diagram of the iron-carbon system because it is not an equilibrium phase. Equilibrium phases form by slow cooling rates that allow sufficient time for diffusion, whereas martensite is usually formed by very high cooling rates.

What are the various phases of iron carbon equilibrium diagram?

Various phases that appear on the Iron- Carbon equilibrium phase diagram are as under: •Austenite •Ferrite •Pearlite •Cementite •Martensite •Ledeburite Definition of structures:

What is iron-carbon diagram?

The Iron-Carbon Diagram: A map of the temperature at which different phase changes occur on very slow heating and cooling in relation to Carbon, is called Iron- Carbon Diagram. Iron- Carbon diagram shows –

Why is iron cementite diagram not a true equilibrium diagram?

Iron-Cementite diagram is not a true equilibrium diagram, since equilibrium means no change of phase with time, however long it may be. Graphite is more stable form of carbon.

What is fe-fe3c equilibrium diagram?

Introduction to the Fe-Fe3C Equilibrium Diagram: Carbon is the most important alloying element in iron which significantly affects the allotropy, structure and properties of iron.