Ab initio molecular dynamics study on local structure and dynamic properties of liquid Ni62Nb38 alloy. (June 2021)

• Record Type: Journal Article
• Authors: Chen, Feiyun; Cao, Chengcheng; Zhong, Qiu; Liu, Jianjun; Yang, Liping; Chen, Zezhong
• Is Part Of: Materials today communications. Volume 27(2021)
• Publication Date: 2021-06
• Subjects: Liquid Ni62Nb38alloy -- Ab initio molecular dynamics -- local structure -- Short-range order -- Electronic structure; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2021.102207
• Languages: English
• ISSNs: 2352-4928

Abstract

Highlights: The local structural evolution and dynamic properties of liquid Ni62 Nb38 alloy during cooling were studied by AIMD. With the decrease of temperature, the local structure tends to change from simple to complex, forming tetrahedral and icosahedral structure. The formation of Ni-Nb chemical bonds is mainly caused by hybridization between Ni and Nb d -states. Abstract: In the temperature range between 1873 K and 1233 K, structural evolution and dynamic properties of liquid Ni62 Nb38 alloy have been studied by ab initio molecular dynamics. The evolution of local structure was characterized by pair distribution functions, structure factors, bond angle distributions, coordination numbers and chemical short-range order parameters, and electronic structure is mainly reflected by the density of states. Self-diffusion coefficients were calculated out to represent dynamic properties. It is found that with the decrease of temperature, short-range order tends to increase and medium-range order can be discovered in the under-cooling system. Meanwhile, a series of complex local structure like tetrahedron and icosahedron gradually forms in the liquid. Moreover, the whole system is hetero-coordinating. During the whole process, both Ni and Nb diffusion coefficients show a decreasing trend, effectively prohibiting nucleation and crystal growth, and it is beneficial to the amorphous transformation of liquid Ni62 Nb38 alloy. The formation of chemical bonds between Ni and Nb atoms is mainly because of the hybridization interaction between Ni and Nb d -states.