What is eutectic phase diagram?

A eutectic phase diagram is found if the Gibbs potential of the solid phase with a miscibility gap becomes larger than the Gibbs potential of the liquid phase. The relation between the eutectic phase diagram and the g-plots for several temperatures is shown in Fig. 2.13.

What is the eutectic point of steel?

The phase just above the eutectoid temperature for plain carbon steels is known as austenite or gamma. We now consider what happens as this phase is cooled through the eutectoid temperature (723°C).

What is the eutectic composition in the iron carbon phase diagram?

Eutectic point is a point where multiple phases meet. For the iron-carbon alloy diagram, the eutectic point is where the lines A1, A3 and ACM meet. The formation of these points is coincidental. At these points, eutectic reactions take place where a liquid phase freezes into a mixture of two solid phases.

How do you explain a phase diagram?

Phase diagram is a graphical representation of the physical states of a substance under different conditions of temperature and pressure. A typical phase diagram has pressure on the y-axis and temperature on the x-axis. As we cross the lines or curves on the phase diagram, a phase change occurs.

What is unary phase diagram?

A unary phase diagram plots the phase changes of one element as a function of tempera- ture and pressure. A binary diagram plots the phase changes as a function of temperature for a system with varying composition of two com- ponents. Phase diagrams are usually constructed with a constant pressure of one atmosphere.

What is isomorphous phase diagram?

Phase diagrams represent the relationship between temperature and the composition of phases present at equilibrium. An isomorphous system is one in which the solid has the same structure for all compositions. The phase diagram shown is the diagram for Cu-Ni, which is an isomorphous alloy system.

What are the phases of steel?

There are only three phases involved in any steel—ferrite, carbide (cementite), and aus- tenite, whereas there are several structures or mixtures of structures.

What is the iron carbon 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 are the types of phase diagram?

There are three main types of binary phase diagrams : Complete solid and liquid solution diagram, Eutectic diagram (including Eutectic diagram with partial solubility of the components in solid state and Eutectic diagram with intermetallic compound) Peritectic diagram.

What is the importance of phase diagram?

Phase diagrams are useful because they allow us to understand in what state matter exists under certain conditions.

How is the temperature related to the eutectic composition?

This composition is known as the eutectic composition and the temperature is known as the eutectic temperature. On a phase diagram the intersection of the eutectic temperature and the eutectic composition gives the eutectic point. Not all binary alloys have a eutectic point, for example, the gold-silver system does not have eutectic point.

Which is the eutectic point in a phase diagram?

The eutectic line is a horizontal line drawn between two one-phase fields a the eutectic temperature. The eutectic point is the exact temperature and composition at which the liquid phase solidifies into two seperate phases at a single temperature. The eutectic point in the Pb-Sn phase diagram is at 185 degrees celcius and approximately 75 at% tin.

When to use eutectoid transformation in Fe C steel?

• Understanding ofCellular transformation (or precipitation): when applied to phase transformation from austenite to pearlite in iron-carbon (Fe-C) steel, such a transformation is also often called eutectoid transformation. • Understanding of the different phases of iron-carbon (Fe-C) steel.

How is the solidus line determined in eutectic?

The solidus line separates the melt+crystal phase from the all crystal phase. NOTE that the solidus and liquidus lines are experimental, they have been determined by melting and cooling many melts at different percent compositions. 3. The eutectic is the point at which all three phases can exist simultaneously, A, B, and melt.