Network connectivity in icosahedral medium-range order of metallic glass: A molecular dynamics simulation

• Network connectivity of icosahedral clusters in TiAl3 is better than TiAl.
• TiAl3 is predicted to have higher strength than TiAl at amorphous state.
• Average connectable icosahedra parameter is a precise and sensitive method.
• Average connectable icosahedra parameter indicates connectivity in higher level.

A molecular dynamics simulation study has been carried out to investigate the evolutions of network connectivities in icosahedral medium-range order of Ti–Al alloys during rapid solidifications. To overcome the shortcomings of previous quantitative methods, average connectable icosahedra parameter is applied to evaluate the network connectivity of interpenetrating connections of icosahedra in the medium-range order of metallic glass. According to the present investigations of the network connectivities in Ti–Al alloys, TiAl3 alloy is predicted to have higher strength than TiAl alloy at amorphous state. Furthermore, the average connectable icosahedra parameter is a more precise and sensitive characterization method compared with previous parameters to describe the network connectivity of icosahedral clusters in a higher level of structural organization. As a good indicator to describe the interpenetrating icosahedral clusters in metallic glasses, the new parameter provides deeper insights into the relationship between network connectivity of icosahedral medium-range order and material properties in amorphous materials.