Presence of intrinsic growth nuclei in overheated and undercooled liquid elements

Abstract

Magnetic field texturing has already shown the possible existence of intrinsic solid nuclei above the melting temperature T m. The transfer of Δ n conduction electrons equalizing the Fermi energies of a particle containing n free electrons and the melt creates an interface electrostatic energy − ε v per volume unit that stabilizes tiny crystals above T m; they act as growth nuclei reducing the undercooling ratio θ=( T− T m)/ T m. The observed θ values and the effective dimensionless surface energies ( α 1ls) eff of 38 elements are used to calculate − ε v which is added to the Gibbs free energy change associated to a crystal formation. The ε v values are equal to 0.217(1−2.5 θ 2) multiplied by Δ H m/ V m the melting heat per volume unit. After melting these crystals above T m2=1.20 T m, θ could tend to the universal value −2/3. A simple formula based on the ε v values is predicting the linear decrease of Δ n/ n with θ and its disappearance for θ 0=−0.63. The free volume Δ V m/ V m and ε v also disappear for θ=−0.63 when Δ V m/ V m is equal to Δ n/ n. The surviving crystal radius is determined by a liquid droplet nucleation model in overheated crystals. A higher stability of tiny crystals is predicted from θ=0 to θ c. The strain energy density determines 0 < θ c⪡+0.2.