The fitting parameters
Using the notations of the papers in the reference list the five fittig
parameters, a, b, c, d, e for cubic crystals or the six fitting parameters,
a1, a2, b, c, d, e for hexagonal crystals
are in the following relations with the physical parameters of the
microstructure:
a =q, where q is the parameter in the average contrast factors of
dislocations in cubic crystals.
b =log(m), where m is the median of the log-normal size distribution
density function.
c =sigma*sqrt(2), where sigma is the variance of the log-normal size
distribution density function. (Often the variance is denoted as
log(sigma).)
d =[2/(Pi*rho)]1/2*b-1, where rho is the
dislocation density and b is the absolute value of the Burgers vector.
e =(1/2)*exp(-1/4)/R*e, where
R*e is the effective outer cut-off radius of dislocations.
Note that M*=R*e*rho1/2.