Study of the effect of grain size on melting temperature of Al nanocrystals by molecular dynamics simulation

This research is devoted to the study of the effect of grain size and structural disorders on the melting behavior of Al nanocrystals under nonequilibrium conditions. The results indicate that T-m is constant and similar to T-m of perfect crystal for nanocrystals of 14 nm and higher. But, by a decrease in the grain size, T-m is significantly reduced. In addition, by further decrease in the size of the grain up to about three times the value of Al-lattice parameter, the behavior of the melt will be similar to the amorphous phase. Since it seems that these behaviors are related to high percentage of grain boundaries in nanocrystalline materials, the structural disorders of the atoms in different regions of nanocrystalline samples are separately studied during heating. The results show that premelting of boundary regions causes the melting process of nanostructure materials to be done within one temperature limit instead of at one temperature point.