What is eutectic structure of iron?
The eutectoid structure in iron has a special name: it is called pearlite (because it has a pearly look). The micrograph (Figure 4.16) shows pearlite.
What is iron 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 is eutectic reaction in iron carbon diagram?
The eutectoid reaction describes the phase transformation of one solid into two different solids. In the Fe-C system, there is a eutectoid point at approximately 0.8wt% C, 723°C. The phase just above the eutectoid temperature for plain carbon steels is known as austenite or gamma.
What is iron carbon phase equilibrium diagram?
The Fe – C diagram (also called the iron – carbon phase or equilibrium diagram) is a graphic representation of the respective microstructure states of the alloy iron – carbon (Fe-C) depending on temperature and carbon content. To explain this diagram, an introduction about metal structures and pure iron must be done.
What is eutectic structure?
(A eutectic or eutectic mixture is a mixture of two or more phases at a particular composition of materials that have the lowest melting point, at which temperature the phases will simultaneously crystalize.
Why is the FE Fe3C phase diagram a metastable phase diagram instead of a true equilibrium phase diagram?
The phase diagram is a metastable phase diagram rather than a true equilibrium phase diagram because the compound iron carbide ( ) formed, cementite, is not a true equilibrium phase. While cementite is typically very stable, it can decompose into iron and carbon under certain conditions.
What is eutectic reaction?
A eutectic reaction is a three-phase reaction, by which, on cooling, a liquid transforms into two solid phases at the same time. It is a phase reaction, but a special one. For example: liquid alloy becomes a solid mixture of alpha and beta at a specific temperature (rather than over a temperature range).
Is iron carbon diagram an 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 is the eutectic composition of carbon for the iron-carbon phase diagram?
The eutectic concentration of carbon is 4.3%. In practice only hypoeutectic alloys are used. These alloys (carbon content from 2.06% to 4.3%) are called cast irons.
What is a eutectic microstructure?
1.1 Microstructure. Eutectics grown from the melt give rise to homogeneous, highly-structured dense materials. The basic microstructure of a regular eutectic consists of non-faceted phases either single-crystal rods or lamellae embedded in a single-crystal matrix as depicted in Figs.
What is a eutectic example?
Examples of Eutectic Systems Sodium chloride and water form a eutectoid when the mixture is 23.3% salt by mass with a eutectic point at -21.2 degrees Celsius. The system is used to make ice cream and to melt ice and snow. The eutectic point of the mixture of ethanol and water is nearly pure ethanol.