An Equation of the State and Surface Properties of Amorphous Iron

It has been shown that three singular points related to an amorphous state can be distinguished in the dependence of the first coordination number k n on packing coefficient k p in the structure of a unicomponent material. The equation of state and properties of iron for both these three amorphous structures and the crystal state are calculated on the basis of the Mie–Lennard-Jones pair interatomic potential. It is shown that the chemical potential becomes minimal at k p = 0.45556 and k n = 6.2793; that is, this packing can be assigned to a thermodynamically stable amorphous structure corresponding to a liquid phase. A point that is energetically equivalent to this phase and has the same value of k n but another value of k p (0.6237) is a thermodynamically unstable amorphous structure corresponding to a solid phase. It was shown that the specific surface energy of an amorphous solid metal is higher than that of the amorphous liquid phase but is lower than the specific surface energy of a crystalline metal. This should lead to the fact that the surface of a crystalline metal will tend to amorphization.