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

Abstract

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 $$2$$ 2 –$$4 \mathrm{nm}$$ 4 nm . Simulated data predicted a decrease in the melting point $${T}_{m}$$ T m of aluminum nanoparticles with an increase in their inverse radius $${r}^{-1}$$ r - 1 according to an almost linear law. The data obtained predicted a higher value of melting temperature compared to crystallization by $$\Delta T=272 \mathrm{K}$$ Δ T = 272 K for a size of $$4\mathrm{ nm}$$ 4 nm and, $$\Delta T=193 K$$ Δ T = 193 K for $$2\mathrm{ nm}$$ 2 nm . The $${T}_{m}$$ T m of the nanoparticles augmented with increasing size, from $$720 K$$ 720 K for $$2 \mathrm{nm}$$ 2 nm to $$827 \mathrm{K}$$ 827 K for $$4\mathrm{ nm}$$ 4 nm . Furthermore, a linear extrapolation of the $${T}_{m}$$ T m as a function of the inverse of the cubic root of the number of atoms yielded a melting temperature of aluminum of $$947 \pm 8 \mathrm{K}$$ 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.