The α-factor is used to predict the solid–liquid
interface
Interface or interfacing may refer to:
Academic journals
* ''Interface'' (journal), by the Electrochemical Society
* '' Interface, Journal of Applied Linguistics'', now merged with ''ITL International Journal of Applied Linguistics''
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type of a material during
solidification
Freezing is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point. In accordance with the internationally established definition, freezing means the solidification phase change of a liquid o ...
.
Method
According to John E. Gruzleski in his book Microstructure Development During Metalcasting (1996):
α = (L/k*T
E)*(η/v)
where
L is
latent heat of fusion
In thermodynamics, the enthalpy of fusion of a substance, also known as (latent) heat of fusion, is the change in its enthalpy resulting from providing energy, typically heat, to a specific quantity of the substance to change its state from a s ...
k is
Boltzmann’s constant
T
E is equilibrium
freezing temperature
η is the number of nearest neighbours an
atom
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons.
Every solid, liquid, gas, and ...
has in the interface
plane
Plane(s) most often refers to:
* Aero- or airplane, a powered, fixed-wing aircraft
* Plane (geometry), a flat, 2-dimensional surface
Plane or planes may also refer to:
Biology
* Plane (tree) or ''Platanus'', wetland native plant
* ''Planes' ...
v is the number of nearest neighbours in the bulk solid
Since L/T
E = ΔS
f
where ΔS
f is the
molar entropy of fusion
In thermodynamics, the entropy of fusion is the increase in entropy when melting a solid substance. This is almost always positive since the degree of disorder increases in the transition from an organized crystalline solid to the disorganized ...
of the material
α = ΔS
f/k(η/v)
According to Martin Glicksman in his book Principles of Solidification : An Introduction to Modern Casting and Crystal Growth Concepts(2011):
α = ΔS
f/R
g(η
1/Z)
where R
g is the
universal gas constant
The molar gas constant (also known as the gas constant, universal gas constant, or ideal gas constant) is denoted by the symbol or . It is the molar equivalent to the Boltzmann constant, expressed in units of energy per temperature increment per ...
,
(η
1/Z) is similar to previous, always 1/4<(η
1/Z)<1
Materials science
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