Temperature effects on growth configurations for Al-Mg bimetallic nanoparticles

The growth of Al atoms on a Mg hexahedral cluster with 587 atoms within the temperature range of 50-550 K is studied by using molecular dynamics and embedded atom method. The energy barriers of typical diffusion processes of Al atoms on Mg clusters are calculated using nudged elastic band method. Radial distribution function is utilized to analyze the growth process. Simulation results demonstrate the temperature dependence of the shape-controlled growth of the bimetallic cluster. The deposited Al atoms are arranged in a hexahedral structure at lower temperature, and a better Mg-core/Al-shell cluster with a nearly spherical structure is obtained at 150 K. As the simulated temperature increases, more and more Al adatoms enter the Mg core, and alloying in the clusters become more apparent.