Effect of local structures and atomic packing on glass forming ability in CuxZr100−x metallic glasses

Using molecular dynamics simulations with embedded atom model potential, we study structural evolution of Cu64.5Zr35.5 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 order, we show that structure of Cu64.5Zr35.5 metallic glass essentially depends on cooling rate. In particular, a decrease of the cooling rate leads to a 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 γmin = 1.5 · 10 9 K/s. Analysing the structure of the glass at γmin, we observe the formation of nano-sized crystalline grain of Cu2Zr intermetallic compound with the structure of Cu2Mg Laves phase. The structure of this compound is isomorphous with that for Cu5Zr intermetallic compound. Both crystal lattices consist of two type 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 and explains the drastic increase of the abundances of these clusters observed at γmin.

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“…For Cu-Zr system, this idea has been strongly supported by molecular dynamics simulations [10][11][12][13][14][15] .…”

Section: Introductionmentioning

confidence: 70%

Cooling rate dependence of simulated Cu64.5Zr35.5 metallic glass structure

Ryltsev

Klumov

Chtchelkatchev

et al. 2016

The Journal of Chemical Physics

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“…In the first group, most polyhedra are stable or solid-like clusters with high density of fivefold bonds. Such as <0, 0, 12, 0>, <0 [51,52]. In contrast, most of the minor polyhedra are usually liquid-like clusters fragmented with high disclination density [4].…”

Section: Resultsmentioning

confidence: 99%

Intrinsic structural defects on medium range in metallic glasses

et al. 2016

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a b s t r a c tTo get insight into the structural defects on medium range in metallic glasses, molecular dynamic simulations on cavitation instability are carried out. It is found that micro voids are prone to nucleate at the sites where atomic clusters are loose packing on medium range. Close-up observation on atomic clusters around the nucleation site shows that there are two kinds of defects on medium range: cavities among the atomic clusters and boundaries between medium range orders. Further investigation shows that the defects are significantly important in both cavitation and shear transformation, which are two intrinsic deformation modes of metallic glasses.

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“…The Voronoi index is represented by a vector notation n 3 , n 4 , n 5 , n 6 where n i denotes the number of shell atoms which are connected by other shell atoms defined by RDF. A cut off distance of 5Å [26] was selected for Voronoi polyhedra (VP) calculation. The total fractions of various VP around Cu and Zr are shown in the Fig.…”

Section: Radial Distribution Function (Rdf) and Voronoi Tessellationmentioning

confidence: 99%

Prediction of glass forming ability in Cu(x)Zr(1-x) alloys using molecular dynamics

Khandpekar¹,

Shrivastava²,

Gowtam³

et al. 2015

Nanosist.: fiz. him. mat.

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Binary Cu x Zr 1−x (x = 0.46, 0.50, 0.58, 0.62) alloy systems were developed using a conventional melting route. Molecular dynamics (MD) simulations have been carried out using the embedded atom method (EAM) potentials. Radial distribution function (RDF) and Voronoi calculations have been conceded for amorphous structure verification. The reduced glass transition temperature (T rg ) has been determined in order to predict the glass forming ability (GFA) of these alloys. T l is found to be a better substitute for T m and the simulated T rg values are seen to be in good agreement with the experimental results in limits of 0.8 -5.4 %.

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Effect of local structures and atomic packing on glass forming ability in CuxZr100−x metallic glasses

Cited by 198 publications

References 33 publications

Cooling rate dependence of simulated Cu64.5Zr35.5 metallic glass structure

Cooling rate dependence of simulated Cu64.5Zr35.5 metallic glass structure

Intrinsic structural defects on medium range in metallic glasses

Prediction of glass forming ability in Cu(x)Zr(1-x) alloys using molecular dynamics

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