Publication Date:
2016-07-21
Description:
Using molecular dynamics simulations with embedded atom model potential, we study structural evolution of Cu 64.5 Zr 35.5 alloy during the cooling in a wide range of cooling rates γ ∈ (1.5 ⋅ 10 9 , 10 13 ) K/s. Investigating short- and medium-range orders, we show that the structure of Cu 64.5 Zr 35.5 metallic glass essentially depends on cooling rate. In particular, a decrease of the cooling rate leads to an increase of abundances of both the icosahedral-like clusters and Frank-Kasper Z16 polyhedra. The amounts of these clusters in the glassy state drastically increase at the γ min = 1.5 ⋅ 10 9 K/s. Analysing the structure of the glass at γ min , we observe the formation of nano-sized crystalline grain of Cu 2 Zr intermetallic compound with the structure of Cu 2 Mg Laves phase. The structure of this compound is isomorphous with that for Cu 5 Zr intermetallic compound. Both crystal lattices consist of two types of clusters: Cu-centered 13-atom icosahedral-like cluster and Zr-centered 17-atom Frank-Kasper polyhedron Z16. That suggests the same structural motifs for the metallic glass and intermetallic compounds of Cu–Zr system and explains the drastic increase of the abundances of these clusters observed at γ min .
Print ISSN:
0021-9606
Electronic ISSN:
1089-7690
Topics:
Chemistry and Pharmacology
,
Physics
