Microstructural Transitions during the Rapid Cooling Process of Liquid Metal Al

From a molecular-dynamics simulation study on the rapid cooling process of liquid metal Al, it is demonstrated that the microscopic structure transitions is mainly determined by the changes of various microstructural configurations. There are tWo obvious phase transition points during the rapid cooling process. The first transition point is consistent with the well-known glass transition. The second one is a new weaker transition at low temperature. The cluster having 7-fold symmetry still exists in the supercooled liquid metal Al, though it occupies only 0.1% of the total number of clusters in the system and disappears below 550K, namely, it can not exist in the glassy state. These results will give us a new way to understand the structural transition at microscopic level.