Abstract
Whether one-component supercooled liquid encounters a spinodal limit at a sufficiently low temperature has been a controversial issue. To explore the homogeneous nucleation limit (HNL) in liquid Al, a series of molecular dynamics simulations have been performed, and a unique technique able to distinguish the critical nucleus from various embryos has been adopted to measure the crystal nucleation time tau(N) of supercooled liquids and evaluate the nucleation energy barrier Delta E-cri* in isothermal crystallization. The estimated kinetic spinodal (i.e., HNL) temperature T-ks and thermodynamic spinodal temperature T-ts are 0.51 Tm and 0.45 Tm, respectively. At the HNL, the nucleation energy barrier Delta E-cri* is discovered to be very small, and a critical slowdown behavior is also observed near T-ks. A careful analysis for the Stokes-Einstein (SE) relation reveals the temperature T-SE of SE relation breakdown is only 0.02 T-m higher than T-ks, and the occurrence of HNL is not affected by whether the SE relation breaks down or not. These results are consistent with previous reports. To some extent, the small gap between T-SE and T-ks can be attributed to a weak glass formation ability of liquid Al.
NSTL
Elsevier