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The phase diagram shows, in pressure–temperature space, the lines of equilibrium or phase boundaries between the three phases of solid, liquid, and gas. The curves on the phase diagram show the points where the free energy (and other derived properties) becomes non-analytic: their derivatives with respect to the coordinates (temperature and ...
The solidus is the locus of temperatures (a curve on a phase diagram) below which a given substance is completely solid (crystallized). The solidus temperature specifies the temperature below which a material is completely solid, [2] and the minimum temperature at which a melt can co-exist with crystals in thermodynamic equilibrium.
A binary phase diagram displaying solid solutions over the full range of relative concentrations. On a phase diagram a solid solution is represented by an area, often labeled with the structure type, which covers the compositional and temperature/pressure ranges. Where the end members are not isostructural there are likely to be two solid ...
TTT diagram of isothermal transformations of a hypoeutectoid carbon steel; showing the main components obtained when cooling the steel and its relation with the Fe-C phase diagram of carbon steels. Austenite is slightly undercooled when quenched below Eutectoid temperature. When given more time, stable microconstituents can form: ferrite and ...
In chemistry, the lever rule is a formula used to determine the mole fraction (x i) or the mass fraction (w i) of each phase of a binary equilibrium phase diagram.It can be used to determine the fraction of liquid and solid phases for a given binary composition and temperature that is between the liquidus and solidus line.
Phase diagram explaining how the pattern forms. First meteoric iron is exclusively composed of taenite. When cooling off it passes a phase boundary where kamacite is exsolved from taenite. Meteoric iron with less than about 6% nickel (hexahedrite) is completely changed to kamacite. Widmanstätten pattern, metallographic polished section
This - Calphad calculated value of numerical derivative - Q has some interesting applications in the field of metal solidification. In fact, Q reflects the phase diagram of the alloy system and its reciprocal has been found to have a relationship with grain size d on solidification, which empirically has been found in some cases to be linear:
These diagrams are used to represent which types of phase changes will occur in a material as it is cooled at different rates. These diagrams are often more useful than time-temperature-transformation diagrams because it is more convenient to cool materials at a certain rate (temperature-variable cooling), than to cool quickly and hold at a ...