Abstract
A novel, non-radiative mechanism is reported by which Frenkel pairs of vacancies and interstitials are generated in molar concentrations far above thermal equilibrium. This mechanism is demonstrated in molecular dynamics (MD) simulations of an aluminum single crystal with a free surface. They suggest that three conditions must be fulfilled: (i) lattice vibrations near the Brillouin zone edge are being excited, (ii) these vibrations proliferate at a sufficiently high rate, and (iii) the sample temperature is above the Debye temperature (but significantly below the melting point). The simulations employed an EAM potential for Al. We attempt to draw a confluence between our MD simulations and recent experiments on flash sintering of aluminum. The simulation results are also consistent with flash experiments on polycrystals and single crystals of zirconium and titanium oxides where the Debye temperature was discovered to be the lower limit for the onset of the flash.
Highlights
Point defects, like vacancies or interstitials, play an important role in crystals
Our molecular dynamics (MD) simulations show that lattice defects are generated if three necessary conditions are satisfied: (i) the specimen temperature T is above the Debye temperature θD, which is qD = 428 K for Al [14], (ii) the phonons
By means of MD simulations of single-crystalline Al we showed, that driving a lattice out of equilibrium by exciting certain phonons more than others can lead to the generation of interstitials and vacancies before the crystal melts
Summary
Any further distribution of generated in molar concentrations far above thermal equilibrium. This mechanism is demonstrated this work must maintain attribution to the in molecular dynamics (MD) simulations of an aluminum single crystal with a free surface. They author(s) and the title of suggest that three conditions must be fulfilled: (i) lattice vibrations near the Brillouin zone edge are the work, journal citation and DOI. The simulation results are consistent with flash experiments on polycrystals and single crystals of zirconium and titanium oxides where the Debye temperature was discovered to be the lower limit for the onset of the flash
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