Thermodynamic, dynamic and structural relaxation in supercooled liquid and glassy Nibelow the critical temperature

Abstract

The thermodynamic, dynamic and structural relaxations of supercooled liquidand glassy Ni have been investigated using molecular dynamics simulationsbased on the embedded atom method. The glass transition temperatureTg is estimated to be 800 K by characterizing the pair correlation function, and the critical temperatureTc is 840 K according to the calculated diffusion constant. Three temperature regionscan be observed as the temperature decreases: (a) in the temperature range840 K≤T≤1000 K, crystallization of supercooled liquid occurs when the characteristicrelaxation time is long enough to reach the incubation timeτ; (b) a complicated region composed of partial crystal and glass will appear within the range810 K≤T<840 K; and (c) glass crystallization can be detected as the temperature is below 810 K. Results fordynamic and structural relaxations indicate that not only the crystallization ofsupercooled liquid but that of the glass derive from the nucleation and growth ofcrystal nuclei, which relates closely to the structural rearrangements of atoms. Atemperature–time-transformation schematic plot has been constructed based on thetemperature dependence of the characteristic relaxation times.