Iron-carbon phase diagram, showing the conditions under which ferrite (α) is stable.

Ferrite or alpha iron (α-Fe) is a materials science term for iron, or a solid solution with iron as the main constituent, with a body centred cubic crystal structure. It is the component which gives steel and cast iron their magnetic properties, and is the classic example of a ferromagnetic material. 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. ... In physical chemistry and materials science, a phase diagram is a type of graph used to show the equilibrium conditions between the thermodynamically-distinct phases. ... The Materials Science Tetrahedron, which often also includes Characterization at the center Materials science is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering. ... In crystallography, the cubic crystal system is the most symmetric of the 7 crystal systems. ... The steel cable of a colliery winding tower. ... 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). ... Ferromagnetism is the phenomenon by which materials, such as iron, in an external magnetic field become magnetized and remain magnetized for a period after the material is no longer in the field. ...

Most "mild" steels (plain carbon steels with up to about 0.2 wt% C) consist mostly of ferrite, with increasing amounts of pearlite (a fine lamellar structure of ferrite and cementite) as the carbon content is increased. Since bainite (shown as ledeburite on the diagram) and pearlite each have ferrite as a component, any iron-carbon alloy will contain some amount of ferrite if it is allowed to reach equilibrium at room temperature. Steel framework Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ... Pearlite occurs at the eutectoid of the iron-carbon phase diagram (near the lower left). ... Cementite or iron carbide is a chemical compound with the formula Fe3C, and an orthorhombic crystal structure. ... Iron-carbon phase diagram, showing the eutectoid temperature and composition, at which bainite can form. ... Chemical equilibrium is the state in which the concentrations of the reactants and products have no net change over time. ...

In pure iron, ferrite is stable below 910°C. Above this temperature the face-centered cubic form of iron, austenite (gamma-iron) is stable. Above 1390°C, up to the melting point at 1534°C, the body-centred cubic crystal structure is again the more stable form of delta-ferrite (δ-Fe). In crystallography, the cubic crystal system is the most symmetric of the 7 crystal systems. ... Iron-carbon phase diagram, showing the conditions under which austenite (γ) is stable in carbon steel. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ...

Only a very small amount of carbon can be dissolved in ferrite; the maximum solubility is about 0.02wt% at 723°C. This is because carbon dissolves in iron interstitially, with the carbon atoms being about twice the diameter of the interstitial "holes", so that each carbon atom is surrounded by a strong local strain field. Hence the enthalpy of mixing is positive (unfavourable), but the contribution of entropy to the free energy of solution stabilises the structure for low carbon content. 723°C also is the minimum temperature at which iron-carbon austenite (0.8 wt% C) is stable; at this temperature there is a eutectoid reaction between ferrite, austenite and cementite. General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... Solubility refers to the ability for a given substance, the solute, to dissolve in a solvent. ... In thermodynamics and molecular chemistry, the enthalpy or heat content (denoted as H or ΔH, or rarely as χ) is a quotient or description of thermodynamic potential of a system, which can be used to calculate the useful work obtainable from a closed thermodynamic system under constant pressure. ... Ice melting - classic example of entropy increasing[1] described in 1862 by Rudolf Clausius as an increase in the disgregation of the molecules of the body of ice. ... The free energy is a measure of the amount of mechanical (or other) work that can be extracted from a system, and is helpful in engineering applications. ... Dissolving table salt in water This article is about a chemical solution; for other uses of the term solution, see solution (disambiguation). ... Eutectoid transformation occurs when a solid solution decomposes into a fixed two solid constituents at a fixed temperature. ... Cementite or iron carbide is a chemical compound with the formula Fe3C, and an orthorhombic crystal structure. ...