Ideal and limiting strength of a Lennard-Jones crystal at temperatures lower than the melting line endpoint temperature: molecular dynamics simulation

VG Baidakov and SP Protsenko, MOLECULAR SIMULATION, 46, 1417-1425 (2020).

DOI: 10.1080/08927022.2020.1836371

The conditions of stability of a stretched face-centered cubic (FCC) crystal against infinitesimal and finite changes in the state parameters have been considered at temperatures lower than that of the endpoint of the melting line V.G. Baidakov, S.P. Protsenko. Phys. Rev. Lett. 95 015701 (2005). Molecular dynamics simulation has been used to calculate effective isothermal elastic moduli, average lifetimes, the work of formation of a critical nucleus and the nucleation rate close to the boundary of the limiting stretching of a Lennard-Jones FCC crystal. States in which the isothermal bulk elastic modulus K is equal to zero, with the shear moduli mu and mu' being nonzero, have been achieved. It is shown that at K < 0 the crystal retains thermodynamic stability. The kinetics of the phase decay of a Lennard-Jones crystal beyond to the line K = 0 has been investigated. It has been found that the decay proceeds by the nucleation mechanism, through the formation and growth of new-phase nuclei. As distinct from small stretchings, at the boundary of limiting ones the nucleus has a form close to spherical.

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