 Pearlite

A lamellar two-phase microconstituent of ferrite and cementite, rather than a single thermodynamic phase. Shorter diffusion distances at greater undercooling generally produce finer lamellae before diffusional transformation is bypassed.

Pearlite is a two-phase microstructure found in steel and other alloys, composed of alternating lamellar (layered) layers of ferrite (α-iron) and cementite (Fe₃C). It forms during the slow cooling of austenitic steel (a high-temperature phase) and is typically observed in low-carbon steels.