Peculiarities of the structure of precrystallization state of amorphous and liquid metals

Peculiarities of crystallization at high undercooling: Analysis of the simulation data for aluminum

“…Our results of simulating the crystallization of amorphous iron and Fe-B alloys [6] show that small (o400 atoms) nanocrystals of iron have a highly imperfect variable structure. Small nanocrystals are characterized by weak coordination of motion of neighboring atoms.…”

“…Models with a free surface were considered in some studies [4,5]. The models that contain many thousands of particles and free surfaces of phases are real enough, as some problems related with the use of periodic boundary conditions are taken off in this case [6]. The size effects, such as size influence on melting heat and temperature of melting of small nanocrystals, their structure, surface tension and frequency spectrum of atomic oscillations, are in focus of many investigations and monographs, for instance [7][8][9][10][11].…”

“…The local pair distribution functions (LPDF) averaged during certain time were determined in Ref. [6] for the places where crystal centers would appear in the future for studying the precrystallization states.…”

“…Melting heat and difference in chemical potentials (a) and the growth velocity (b) of small nanocrystals plotted against their size, T¼ 400 K; (a) the squares are the measured data of DH(r); the values of Dm(r), which correspond to them, are given by circles, the solid line is calculated by formula Dm r ¼Dm T (1À r 0 /r); (b) circles are the measured data of u; the dashed line is calculated according to(5) and the solid line corresponds to(6).…”

Computer Modeling of Physical Phenomena and Processes

“…Actually, studying many processes with phase transitions, periodic boundary conditions in all directions do not give a good approach [12]. Until recently, researchers used only periodic boundary conditions in many works because computer facilities did not allow to model systems with a large enough number of atoms.…”