Effect of aluminum nanoparticle size on phase transitions: a molecular dynamics study.

Isothermal molecular dynamics simulations were carried out with the embedded-atom method as a potential to predict the melting and crystallization temperatures of nanometric sized aluminum particles in the range of 2 – 4 nm . Simulated data predicted a decrease in the melting point T m of aluminum nanoparticles with an increase in their inverse radius r - 1 according to an almost linear law. The data obtained predicted a higher value of melting temperature compared to crystallization by Δ T = 272 K for a size of 4 nm and, Δ T = 193 K for 2 nm . The T m of the nanoparticles augmented with increasing size, from 720 K for 2 nm to 827 K for 4 nm . Furthermore, a linear extrapolation of the T m as a function of the inverse of the cubic root of the number of atoms yielded a melting temperature of aluminum of 947 ± 8 K , which is similar to previous estimations. Finally, when the number of atoms increased the number of face-centered cubic (FCC) structural units also increased, and the amorphous structure decreased. [ABSTRACT FROM AUTHOR]