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Second-Nearest-Neighbor Correlations from Connection of Atomic Packing Motifs in Metallic Glasses and Liquids.

Ding J, Ma E, Asta M, Ritchie RO - Sci Rep (2015)

Bottom Line: The analysis was conducted from the perspective of different connection schemes of atomic packing motifs, based on the number of shared atoms between two linked coordination polyhedra.These properties of the connections and the resultant atomic correlations are generally the same for different types of packing motifs in different alloys.Increasing ordering and cluster connection during cooling, however, may tune the position and intensity of the split peaks.

View Article: PubMed Central - PubMed

Affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

ABSTRACT
Using molecular dynamics simulations, we have studied the atomic correlations characterizing the second peak in the radial distribution function (RDF) of metallic glasses and liquids. The analysis was conducted from the perspective of different connection schemes of atomic packing motifs, based on the number of shared atoms between two linked coordination polyhedra. The results demonstrate that the cluster connections by face-sharing, specifically with three common atoms, are most favored when transitioning from the liquid to glassy state, and exhibit the stiffest elastic response during shear deformation. These properties of the connections and the resultant atomic correlations are generally the same for different types of packing motifs in different alloys. Splitting of the second RDF peak was observed for the inherent structure of the equilibrium liquid, originating solely from cluster connections; this trait can then be inherited in the metallic glass formed via subsequent quenching of the parent liquid through the glass transition, in the absence of any additional type of local structural order. Increasing ordering and cluster connection during cooling, however, may tune the position and intensity of the split peaks.

No MeSH data available.


Related in: MedlinePlus

(a) The correlation between average bond length R1 and average distance (R2*) of the second nearest-neighbors, for the four cluster connection schemes. Each data point is from each species in the samples listed in Table 1. The solid lines are from a geometric calculation, as described in the text. (b) The average number of connected clusters versus NN coordination number for each species of the studied samples (in Table 1) at their corresponding liquidus temperatures. We calculate R1 and CN for each species, in each sample. For example, Cu in Cu64Zr36 and Zr46Cu46Al8 have different measured R1 and CN and they are all used in Fig. 3.
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f3: (a) The correlation between average bond length R1 and average distance (R2*) of the second nearest-neighbors, for the four cluster connection schemes. Each data point is from each species in the samples listed in Table 1. The solid lines are from a geometric calculation, as described in the text. (b) The average number of connected clusters versus NN coordination number for each species of the studied samples (in Table 1) at their corresponding liquidus temperatures. We calculate R1 and CN for each species, in each sample. For example, Cu in Cu64Zr36 and Zr46Cu46Al8 have different measured R1 and CN and they are all used in Fig. 3.

Mentions: The results are plotted in Fig. 3(a), where each data point represents one species for a sample listed in Table 1, and the solid lines represent the predictions. As can be seen in Fig. 3(a), the MD simulation results closely match the calculated . This supports the notion that the atomic cluster connection is primarily responsible for the second-peak locations in the RDF.


Second-Nearest-Neighbor Correlations from Connection of Atomic Packing Motifs in Metallic Glasses and Liquids.

Ding J, Ma E, Asta M, Ritchie RO - Sci Rep (2015)

(a) The correlation between average bond length R1 and average distance (R2*) of the second nearest-neighbors, for the four cluster connection schemes. Each data point is from each species in the samples listed in Table 1. The solid lines are from a geometric calculation, as described in the text. (b) The average number of connected clusters versus NN coordination number for each species of the studied samples (in Table 1) at their corresponding liquidus temperatures. We calculate R1 and CN for each species, in each sample. For example, Cu in Cu64Zr36 and Zr46Cu46Al8 have different measured R1 and CN and they are all used in Fig. 3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663502&req=5

f3: (a) The correlation between average bond length R1 and average distance (R2*) of the second nearest-neighbors, for the four cluster connection schemes. Each data point is from each species in the samples listed in Table 1. The solid lines are from a geometric calculation, as described in the text. (b) The average number of connected clusters versus NN coordination number for each species of the studied samples (in Table 1) at their corresponding liquidus temperatures. We calculate R1 and CN for each species, in each sample. For example, Cu in Cu64Zr36 and Zr46Cu46Al8 have different measured R1 and CN and they are all used in Fig. 3.
Mentions: The results are plotted in Fig. 3(a), where each data point represents one species for a sample listed in Table 1, and the solid lines represent the predictions. As can be seen in Fig. 3(a), the MD simulation results closely match the calculated . This supports the notion that the atomic cluster connection is primarily responsible for the second-peak locations in the RDF.

Bottom Line: The analysis was conducted from the perspective of different connection schemes of atomic packing motifs, based on the number of shared atoms between two linked coordination polyhedra.These properties of the connections and the resultant atomic correlations are generally the same for different types of packing motifs in different alloys.Increasing ordering and cluster connection during cooling, however, may tune the position and intensity of the split peaks.

View Article: PubMed Central - PubMed

Affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

ABSTRACT
Using molecular dynamics simulations, we have studied the atomic correlations characterizing the second peak in the radial distribution function (RDF) of metallic glasses and liquids. The analysis was conducted from the perspective of different connection schemes of atomic packing motifs, based on the number of shared atoms between two linked coordination polyhedra. The results demonstrate that the cluster connections by face-sharing, specifically with three common atoms, are most favored when transitioning from the liquid to glassy state, and exhibit the stiffest elastic response during shear deformation. These properties of the connections and the resultant atomic correlations are generally the same for different types of packing motifs in different alloys. Splitting of the second RDF peak was observed for the inherent structure of the equilibrium liquid, originating solely from cluster connections; this trait can then be inherited in the metallic glass formed via subsequent quenching of the parent liquid through the glass transition, in the absence of any additional type of local structural order. Increasing ordering and cluster connection during cooling, however, may tune the position and intensity of the split peaks.

No MeSH data available.


Related in: MedlinePlus