Molecular dynamics simulations on the connectivity of topologically close-packed clusters in TiAl3 alloys

Abstract

Presently, there has been increasing attention on TiAl3, which is commonly used for fabricating power aviation devices owing to its good oxidation resistance and outstanding mechanical properties in high-temperature. As the microstructures determine the macroscopic properties of a material, we investigated the connectivity of icosahedral central atoms in TiAl3 using conventional methods in this study. The topologically close-packed (TCP) structures are present in supercooled liquids, metallic glasses, and metallic liquids. They are intrinsic to liquid metals and are an essential character of the structure in metallic glasses (MGs). However, because of the lack of the concept of connectivity of the TCP structures, we investigated connectivity from the icosahedral central atoms to TCP structures, and a formula was proposed to calculate the connectivity of the TCP structures. Based on the results, low temperatures and cooling rates are conducive to generate high connectivity between icosahedral central atoms and TCP structures. The proposed formula can characterize the connectivity of the TCP structures. These findings open new opportunities for conducting research on the connectivity of clusters in binary alloys.