Local structure orders and glass forming ability of Ni-Nb liquids

Journal Article · Fri May 04 00:00:00 EDT 2018 · Intermetallics

DOI:https://doi.org/10.1016/j.intermet.2018.04.021· OSTI ID:1459544

Wen, T. Q. ^[1]; Zhang, Y. ^[2]; Wang, C. Z. ^[3]; Wang, N.  ^[4]; Ho, K. M. ^[3]; Kramer, M. J. ^[5]

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1. Northwestern Polytechnical Univ., Xi'an (China). MOE Key Lab. of Materials Physics and Chemistry under Extraordinary Conditions. School of Natural and Applied Sciences; Ames Lab. and Iowa State Univ., Ames, IA (United States)
2. Ames Lab. and Iowa State Univ., Ames, IA (United States)
3. Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
4. Northwestern Polytechnical Univ., Xi'an (China). MOE Key Lab. of Materials Physics and Chemistry under Extraordinary Conditions. School of Natural and Applied Sciences
5. Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Materials Science and Engineering

In this paper, ab initio molecular dynamics simulations were performed to study the atomistic structures of Ni₄₈Nb₅₂, Ni_59.5Nb_40.5 and Ni₇₅Nb₂₅ liquids near their melting temperatures. It is found that the total coordination number only changes slightly across the compositions. However, there is significant difference in the chemical ordering. The Cluster Alignment method was used to identify the dominant local structure motifs. It is found that distorted and perfect icosahedral clusters are the most popular motifs around Ni atoms, while Z14, Z15, and Z16 Frank-Kasper polyhedra are dominant around Nb atoms. Among the three compositions, the eutectic composition (Ni_59.5Nb_40.5) has the largest population of these dominant motifs and the highest degree of five-fold local symmetry. Chemical order in the distorted icosahedral motif is studied and the occupation probability of Nb in the distorted region is found to be much different from other sites. The network formed by distorted and perfect icosahedral clusters and that by the interconnection of the perfect icosahedra, Z14, Z15, and Z16 motifs are the strongest at the eutectic composition. Finally, the high percentage of perfect and distorted icosahedral clusters and their strong network structures in this system (especially around the eutectic composition) correlate well with the excellent glass forming ability in this system.

• Research Organization: Ames Lab. and Iowa State Univ., Ames, IA (United States); Northwestern Polytechnical Univ., Xi'an (China)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); National Natural Science Foundation of China (NSFC)
• Grant/Contract Number: AC02-07CH11358; 51671160; 51271149
• OSTI ID: 1459544
• Report Number(s): IS-J-9699; PII: S0966979517309810
• Journal Information: Intermetallics, Vol. 98; ISSN 0966-9795
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
metallic glasses
glass forming ability
local structure and chemical orders
ab-initio calculation and molecular dynamics simulation