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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

Radial distribution functions g(r) for (a) Ni80P20 and (b) Zr46Cu46Al8 MGs at 300 K obtained by MD simulation with a cooling rate of 1010 K/s (Samples #5 and 8, respectively, in Table 1).The decomposed radial distribution functions for nearest-neighbors (NN), second nearest neighbor atoms via 1-atom, 2-atom, 3-atom and 4-atom cluster connections, are also included. The insets show a magnified RDF at large distances.
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f2: Radial distribution functions g(r) for (a) Ni80P20 and (b) Zr46Cu46Al8 MGs at 300 K obtained by MD simulation with a cooling rate of 1010 K/s (Samples #5 and 8, respectively, in Table 1).The decomposed radial distribution functions for nearest-neighbors (NN), second nearest neighbor atoms via 1-atom, 2-atom, 3-atom and 4-atom cluster connections, are also included. The insets show a magnified RDF at large distances.

Mentions: In Fig. 2, the g(r) for Ni80P20 (sample #5) and Zr46Cu46Al8 (sample #8) MGs at 300 K are evaluated up to large atomic separations (20 Å). The red arrows in Fig. 2(a) indicate the splitting of the second peak for Ni80P20, similar to that observed in Fig. 1(a) and in previous experiments and simulations in the literature22253136. Note that not all MGs exhibit split second peaks, e.g., see the Zr46Cu46Al8 case in Fig. 2(b) and further discussions below.


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)

Radial distribution functions g(r) for (a) Ni80P20 and (b) Zr46Cu46Al8 MGs at 300 K obtained by MD simulation with a cooling rate of 1010 K/s (Samples #5 and 8, respectively, in Table 1).The decomposed radial distribution functions for nearest-neighbors (NN), second nearest neighbor atoms via 1-atom, 2-atom, 3-atom and 4-atom cluster connections, are also included. The insets show a magnified RDF at large distances.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Radial distribution functions g(r) for (a) Ni80P20 and (b) Zr46Cu46Al8 MGs at 300 K obtained by MD simulation with a cooling rate of 1010 K/s (Samples #5 and 8, respectively, in Table 1).The decomposed radial distribution functions for nearest-neighbors (NN), second nearest neighbor atoms via 1-atom, 2-atom, 3-atom and 4-atom cluster connections, are also included. The insets show a magnified RDF at large distances.
Mentions: In Fig. 2, the g(r) for Ni80P20 (sample #5) and Zr46Cu46Al8 (sample #8) MGs at 300 K are evaluated up to large atomic separations (20 Å). The red arrows in Fig. 2(a) indicate the splitting of the second peak for Ni80P20, similar to that observed in Fig. 1(a) and in previous experiments and simulations in the literature22253136. Note that not all MGs exhibit split second peaks, e.g., see the Zr46Cu46Al8 case in Fig. 2(b) and further discussions below.

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