Abstract:From the molecular dynamics simulation on the microstructural transitions of Al liquid metal during rapid cooling processes, it is demonstrated that various aggregates are formed accidentally and randomly in both liquid state and glassy state, however, once they have been formed, some of them are relatively stable and can not be dissociated in the following runs. As an example, the stability of icosahedral aggregates can be expressed quantitatively by their lifetime or repeating times, some aggregates can be created repeatedly in both isothermal process and rapid cooling processes. The lifetimes of these aggregates generally increase with decreasing temperature, and increase remarkably below the glass transition temperatureTg. The number of aggregates having a longer lifetime also increases with decreasing temperature.

Key words: stability　microstructure　liquid metal　rapid cooling　computer simulation