Atomic structure of amorphous Mg40Cu35Ti25 alloy: An ab initio molecular dynamics study

Ab initio molecular dynamics simulations are carried out to model amorphous Mg40Cu35Ti25 and its local structural packing are investigated using a variety of analyzing techniques. Cu-atoms commonly form 12 fold coordinated clusters and some of which are perfect or defective types icosahedrons, implying an icosohedral short range order around Cu atoms. Mg and Ti atoms, on the other hand, favor to structure in higher coordinated polyhedrons. The coordination number of Ti atoms is slightly less than Mg atoms. The immiscibility effect between Ti and Mg is reflected by a low fraction of Mg–Ti bonding in the model. The atomic packing of Mg40Cu35Ti25 appears to be noticeably different from that of Mg–Cu–X (X=Y and Gd) metallic glasses even though all these materials exhibit primarily the same type of bonding natures.

► Amorphous Mg40Cu35Ti25 is modeled using an ab initio technique.
► Cu-atoms commonly form perfect or defective types icosahedrons.
► The immiscibility effect yields a low fraction of Mg–Ti bonding in the model.
► The atomic packing of Mg40Cu35Ti25 differs from that of Mg–Cu–X (X=Y and Gd) glasses.