Pearlite occurs at the eutectoid of the iron-carbon phase diagram (near the lower left).

Pearlite is a two-phased, lamellar (or layered) structure composed of alternating layers of alpha-ferrite (88 wt%) and cementite (12%) that occurs in some steels and cast irons. It forms by a eutectoid reaction as austenite is slowly cooled below 727°C. The eutectoid composition of Austenite is approximately 0.8% carbon [1]; steel with less carbon content will contain a corresponding proportion of relatively pure ferrite crystallites that do not participate in the eutectoid reaction and cannot transform into pearlite. Image File history File links An English version of Diag phase fer carbone. ... Image File history File links An English version of Diag phase fer carbone. ... Eutectoid transformation occurs when a solid solution decomposes into a fixed two solid constituents at a fixed temperature. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... Lamellar structures or microstructures are composed of fine, alternating layers of different materials in the form of lamellae. ... Iron-carbon phase diagram, showing the conditions under which ferrite (α) is stable. ... Cementite or iron carbide is a chemical compound with the formula Fe3C, and an orthorhombic crystal structure. ... For other uses, see Steel (disambiguation). ... Cast iron usually refers to grey cast iron, but can mean any of a group of iron-based alloys containing more than 2% carbon (alloys with less carbon are carbon steel by definition). ... Eutectoid transformation occurs when a solid solution decomposes into a fixed two solid constituents at a fixed temperature. ... Iron-carbon phase diagram, showing the conditions under which austenite (γ) is stable in carbon steel. ... For other uses, see Carbon (disambiguation). ... Ferrite may refer to: Ferrite (magnet)s (e. ...

The appearance of pearlite under the microscope resembles mother of pearl (also a lamellar structure), from which it takes its name. A microscope (Greek: (micron) = small + (skopein) = to look at) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ... “Mother of Pearl” redirects here. ...

A similar structure with lamelle much smaller than the wavelength of visible light lacks this pearlescent appearance. Called bainite, it is prepared by more rapid cooling. Unlike pearlite, whose formation involves the diffusion of all atoms, bainite grows by a displacive transformation mechanism. For other uses, see Wavelength (disambiguation). ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... Iron-carbon phase diagram, showing the eutectoid temperature and composition, at which bainite can form. ...

References

Comprehensive information on pearlite

1. Thorough discussion of pearlite formation.