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Key thermophysical properties of phase-change materials include: Melting point (T m), Heat of fusion (ΔH fus), Specific heat (c p) (of solid and liquid phase), Density (ρ) (of solid and liquid phase) and thermal conductivity. Values such as volume change and volumetric heat capacity can be calculated there from.
GeSbTe (germanium-antimony-tellurium or GST) is a phase-change material from the group of chalcogenide glasses used in rewritable optical discs and phase-change memory applications. Its recrystallization time is 20 nanoseconds, allowing bitrates of up to 35 Mbit /s to be written and direct overwrite capability up to 10 6 cycles.
In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter : solid , liquid , and gas , and in rare cases, plasma .
More precisely, a phase is a region of space (a thermodynamic system), throughout which all physical properties of a material are essentially uniform. [1] [2]: 86 [3]: 3 Examples of physical properties include density, index of refraction, magnetization and chemical composition.
The classical Stefan problem deals with stationary materials with constant thermophysical properties (usually irrespective of phase), a constant phase change temperature and, in the example above, an instantaneous switch from the initial temperature to a distinct value at the boundary.
Phase transitions (phase changes) that help describe polymorphism include polymorphic transitions as well as melting and vaporization transitions. According to IUPAC, a polymorphic transition is "A reversible transition of a solid crystalline phase at a certain temperature and pressure (the inversion point) to another phase of the same chemical composition with a different crystal structure."
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In addition to the use of AlSi alloys as a structural material, in which the mechanical properties are paramount, another area of application is latent heat storage. In the phase change of the alloy at 577 °C, thermal energy can be stored in the form of the enthalpy of fusion. AlSi can therefore also be used as a metallic phase change material ...