Iron-carbon phase diagram & basic definitionsFor more help contact meMuhammad Umair BukhariEngr.umair.bukhari@gmail.comwww.bzuiam.webs.com03136050151Alloy: A metallic substance that is composed of two or more elementsAustenite: Face-centered cubic iron or an iron alloy based on this structure.Bainite: The product of the final transformation of austenite decomposition

Binary Eutectic: In this context, it means a phase diagram that consists of two elemwnts that are not completely soluble in the solid stateBinary Isomorphous: In this context, it means a phase diagram that consists of two elements that are completely soluble in both the liquid and solid states.Body-centered: A structure in which eery atom is surrounded by eight ad!acent atoms, whether the atom is located at a corner or at the center of a unit cell. Cementite: The second phase formed when carbon is in excess of the solubility limit. Component: "ither a pure metal or a compound of which an alloy is composed. Compositions: The concentrations of all components or elements that are found in an alloy. Constituents: #eering to form, compose, or ma$e up a unit or whole: componentCritical point: %oint where the densities of liquid and apor become equal and the interface between the two anishes. Aboe this point, only one phase can existDelta iron: The body-centered cubic phase which results when austenite is no longer the most stable form of iron. "xists between &'(& and &))& degrees F, has *++ lattice structure and is magneticDilatometer: An instrument used to measure thermal expansion in solids, liquids, and gases. Eutectic: A eutectic system occurs when a liquid phase tramsforms directly to a two-phase solid. Eutectoid: A eutectoid system occurs when a single-phase solid transforms directly to a two-phase solidFace-centered: A structure in which there is an atom at the corner of each unit cell and one in the center of each face, but no atom in the center of the cube. Ferrite: *ody-centered cubic iron or an iron alloy based on this structureFine pearlite:,esults from thin lamellae when cooling rates are accelerated and diffusion is limited to shorter distancesFree Energy: A function of the internal energy of a system - a measure of entropy of a system Heterogeneous system: -hen a system is composed of multiple phasesHomogeneous system: -hen only one phase is present in the systemHypereutectoid: .ypereutectoid systems exist below the eutectoid temperature.Hypoeutectoid: .ypoeutectoid systems exist aboe the eutectoid temperatureIsomorphus: .aing the same structure. In the phase diagram sense, isomorphicity means haing the same crystal structure or complete solid solubility for all compositions.Incongruent phase transformation: This is a phase transformation where at least one of the phases inoled undergoes a change in compositionLamellae: A thin scale, plate, or layer of phases Ledeburite: "utectic of cast iron. It exists when the carbon content is greater than & percent. It contains /.0 percent carbon in combination with iron. Leer rule: A mathematical expression whereby the relatie phase amounts in a two-phase alloy at equilibrium may be computedLi!uidus Line: 1n a binary phase diagram, that line or boundary separating liquid and liquid 2 solid phase regions. For an alloy, the liquidus temperature is that temperature at which a solid phase first forms under conditions of equilibrium cooling"artensite: An unstable polymorphic phase of iron which forms at temperatures below the eutectoid because the face-centered cubic structure of austenite becomes unstable. It changes spontaneously to a body-centered structure by shearing action, not diffusion."ass spectrometer: An instrument used to separate charged particles from a prepared beam by means of an electromagnetic field and to photograph the resulting distribution or spectrum of masses"icrostructure: #tructure of the phases in a material. +an only be seen with an optical or electron mircoscope. #earlite: A lamellar mixture of ferrite and carbide formed by decomposing austenite of eutectoid composition. #hase: A homogeneous portion of a system that has uniform physical and chemical characteristics#hase diagram: A graphical representation of the relationships between enironmental constraints, composition, and regions of phase stability, ordinarily under conditions of equilibrium. #olymorphic: The ability of a solid material to exist in more than one form or crystal structure. $uench: To rapidly cool %eference &tate: 3sually an elements most stable state at a gien temperature &olidus Line: 1n a phase diagram, the locus of points at which solidification is complete upon equilibrium cooling, or at which melting begins upon equilibrium heating.&olubility: The amount of substance that will dissole in a gien amount of another substance. 'ie line: A hori4ontal line constructed across a two phase region of a binary phase diagram5 its intersections with the phase boundaries on either end represent the equilibrium conditions of the respectie phases at the temperature in question. (ray diffraction: The scattering of x-rays by atoms in a crystal, producing a diffraction pattern that yields information about the structure of the crystal(ray flourescence: A method of determining the amount of an element present in a substance by bombarding it with electrons and measuring the intensity of the charicteristic x-rays that are gien off by the sample.