Correlation between local structures and glass forming ability of liquid MgxZn1 − x alloys

•The local structures of liquid MgxZn1 − x alloys have been characterized.•The strongest chemical SRO exists in the glass former melt Mg70Zn30.•The icosahedral 1551 bonding pairs increase greatly for the Mg70Zn30 liquid alloy.•The self-diffusion coefficients reach minima for the Mg70Zn30 liquid alloy.

The liquid structures of a series of Mg-Zn alloys have been investigated in the present work by means of ab initio molecular dynamic simulation. Strong chemical short-range orders are observed for the eutectic alloy Mg70Zn30, i.e. the best glass former of Mg-Zn binary alloys, which is consistent with the experiment results. The pair analysis indicates the extraordinary abundance of icosahedral clusters in this eutectic liquid alloy. Furthermore, the self-diffusion coefficients of Mg and Zn reach minimum for the Mg70Zn30 alloy. The entire results offer an interpretation for the better glass forming ability of the Mg70Zn30 alloy.